Quick Answer: By cost per gram of protein, the cheapest reliable sources are dried lentils and beans, eggs, tinned fish, milk and cottage cheese, chicken thighs bought in bulk, tofu, and canned tuna. Dried pulses win by a wide margin but need soaking; eggs and tinned fish are the best value for anything you need in under five minutes. The mistake most people make is buying protein by package price rather than by cost per gram.

Protein is usually the single largest line in a grocery bill, and it’s also the nutrient most worth getting right - it keeps you full, preserves muscle, and does more for appetite control than anything else on the plate.

The useful comparison isn’t what a pack costs. It’s what a gram of protein costs, and the rankings shift substantially once you do that arithmetic.

How do you actually compare protein costs?

One calculation, done once per item, and it changes what goes in the trolley.

The formula: package price divided by total grams of protein in the package.

Total protein = protein per 100g on the label, multiplied by the package weight in hundreds of grams.

Worked example. A 400g tin of chickpeas at 90p, with 7g protein per 100g:

• Total protein: 4 x 7 = 28g
• Cost per gram: 90 / 28 = 3.2p per gram

Versus 500g of dried red lentils at £1.50, with 24g protein per 100g:

• Total protein: 5 x 24 = 120g
• Cost per gram: 150 / 120 = 1.25p per gram

The dried lentils are roughly two and a half times better value, and this pattern - dried versus tinned - holds across every pulse.

Two adjustments worth making:

Account for cooking weight. Dried pulses roughly double or triple in weight when cooked, but the protein doesn’t change - so calculate on dry weight, which is what you paid for.

Account for what you’ll actually eat. A cheap source you don’t like is infinitely expensive per gram consumed. This is the reason the theoretically-cheapest option isn’t always the right one, and why the list below balances cost with usability.

The seven, ranked

Roughly ordered by cost per gram, with the practical caveats.

1. Dried lentils and beans - by far the cheapest.

Red lentils, green lentils, chickpeas, black beans, kidney beans. Around 20-26g protein per 100g dry. Red lentils need no soaking and cook in 15 minutes, which makes them the most practical of the group.

2. Eggs - the best value for convenience.

About 6-7g per egg. No preparation beyond cooking, extremely versatile, and they keep for weeks. The single best cost-to-convenience ratio on this list.

3. Tinned fish - sardines, mackerel, tuna.

Around 20-25g protein per tin. Sardines and mackerel are usually cheaper than tuna and bring omega-3 fats and, with the bones, calcium. Genuinely underrated and stocked in every shop.

4. Milk, yoghurt, and cottage cheese.

Milk is around 3.5g per 100ml; Greek yoghurt around 9-10g per 100g; cottage cheese around 11-12g. Cottage cheese is the best value of the three and the one people overlook. Large tubs of plain yoghurt are far better value than individual pots.

5. Chicken thighs, bought large.

Around 18-20g per 100g raw. Thighs are consistently cheaper than breast and more forgiving to cook. Buying a large pack and freezing in portions is where the saving is.

6. Tofu and soya products.

Around 8-16g per 100g depending on firmness. Firm and extra-firm are better value per gram of protein. Cheap in larger blocks, expensive in small ones.

7. Oats and peanut butter - the supporting cast.

Oats around 11-13g per 100g; peanut butter around 25g per 100g. Neither is a primary protein source, and both add meaningfully across a day at very low cost.

What’s expensive: protein bars, ready-cooked chicken, pre-portioned anything, and most meat substitutes - typically several times the cost per gram of the whole ingredients they’re made from.

How do you get the price down further?

Seven tactics, roughly in order of how much they save.

1. Buy dried rather than tinned. The single biggest saving, typically 50-70 percent on pulses. The barrier is soaking time, and a slow cooker or a pressure cooker removes it entirely.

2. Cook a large batch once a week. Cook a full bag of dried chickpeas or beans, portion, and freeze. Twenty minutes of active time produces the convenience of tins at the cost of dried, which is the whole trick.

3. Buy the largest unit you’ll use before it spoils. Price per unit falls with size on almost everything. The constraint is spoilage and storage, not the arithmetic.

4. Use cheaper cuts. Thighs over breast, whole chicken over pieces, minced beef with higher fat over lean. A whole chicken jointed at home is dramatically cheaper per gram than the same bird as portions, and the carcass makes stock.

5. Combine expensive and cheap in one dish. Half the mince, half the lentils, in a bolognese or a chilli. Nobody notices, the protein content is similar, and the cost halves. This is the most effective single tactic for anyone cooking for a family.

6. Buy frozen. Frozen fish and frozen chicken are cheaper than fresh, don’t spoil, and are nutritionally equivalent. Frozen peas at around 5g protein per 100g are a genuinely useful cheap addition that nobody counts.

7. Shop the reduced section deliberately and freeze immediately. Meat and fish reduced near their date freeze perfectly. Going at the right time of day for your local shop is worth more than any coupon.

On protein powder: worth calculating rather than assuming. Bulk unflavoured whey often comes out competitive with whole foods per gram, and flavoured single-serve products rarely do. It’s a convenience purchase that sometimes happens to be economical.

Seven Mistakes That Make Protein Cost More Than It Should

Mistake 1: Buying by package price rather than cost per gram. The ‘cheap’ pack is frequently the expensive one. One calculation per item, done once, and you never have to think about it again.

Mistake 2: Paying for convenience formats. Pre-cooked, pre-portioned, pre-marinated, and ready-shredded all carry substantial premiums. The saving from batch-cooking is almost entirely this.

Mistake 3: Treating protein bars as food rather than as convenience. Often several times the cost per gram of eggs or tinned fish. Fine occasionally; expensive as a habit.

Mistake 4: Buying lean cuts by default. Chicken breast and lean mince cost considerably more per gram of protein than thighs and standard mince, and the difference in the finished dish is small once the fat is drained.

Mistake 5: Not counting the protein in ordinary food. Bread, pasta, rice, oats, and vegetables all contribute, and it adds up to a meaningful share of a day’s intake. People frequently buy more expensive protein than they need because they’re not counting what’s already there.

Mistake 6: Letting fresh protein spoil. The most expensive protein is the chicken you threw away. Freeze on the day of purchase if you’re not cooking it within two days.

Mistake 7 - the one that undoes everything: buying cheap food you don’t enjoy eating. A cupboard of dried beans nobody wants is a false economy, and the whole point is what actually gets eaten. Start with one or two swaps you’ll genuinely stick with rather than restructuring the entire shop at once.

FAQ: Cheap Protein Questions, Answered

How much protein do I actually need?

Roughly 0.8g per kilogram of bodyweight is the general minimum for adults, and around 1.2-1.6g/kg is commonly recommended for people training regularly or maintaining muscle with age. Distribute it across meals rather than concentrating it in one.

Is plant protein as good as animal protein?

Animal sources are complete and generally better absorbed. Plant sources vary in their amino acid profiles, and eating a range across the day - pulses with grains, for instance - covers it comfortably. Anyone eating mostly plants should aim toward the higher end of the intake range.

Are tinned beans really that much worse value?

Roughly two to three times the cost per gram compared with dried. They’re also fast, need no planning, and require no cooking - which is a real benefit. Batch-cooking dried beans and freezing them gets you both.

Does cooking method affect protein content?

Not meaningfully. Protein is stable through normal cooking. Weight changes as water is lost or absorbed, which is why comparing raw and cooked weights confuses the arithmetic - compare on the state you bought it in.

Is it worth buying protein powder on a budget?

Run the numbers on bulk unflavoured whey - it’s often competitive with whole foods and beats convenience formats comfortably. It’s not a nutritional necessity, and it’s a reasonable purchase if it’s what makes hitting your intake realistic.

TL;DR:

• Compare cost per gram of protein, not package price - it changes the rankings substantially
• Dried pulses win by a wide margin; eggs and tinned fish win on convenience
• Cottage cheese is the most overlooked good-value dairy protein
• Thighs over breast, whole chicken over portions, frozen over fresh
• Half-mince-half-lentils in any mince dish halves the cost and nobody notices
• Count the protein already in bread, oats, pasta, and vegetables before buying more

The cheapest protein is the one you’ll actually cook. Run the per-gram number once on the six things you buy most, and the rest takes care of itself.