The Hidden Costs of 'Commission-Free' Trading Apps

"Commission-free" is one of the most effective marketing phrases in finance. It's also incomplete. A broker still has to make money — so if it isn't charging a commission, the cost has moved somewhere less visible.

Where the money actually comes from

Payment for order flow (PFOF)

Some US brokers are paid by market makers to route your orders to them. It's legal and disclosed, but it means the broker's incentives aren't purely aligned with getting you the best price. The practical effect is usually small per trade, but it's why the app is "free."

The spread

Even with no commission, you buy at the ask and sell at the bid. That gap — the spread — is a real cost on every trade. On liquid US stocks it's tiny; on crypto "instant buy" or CFDs it can be several times what you'd pay on a pro interface.

Currency conversion (FX) fees

Buying US stocks from a GBP or EUR account? The FX conversion fee can easily dwarf any commission. Always look for the percentage charged on conversion, not just the headline "£0 commission."

Market-data and platform fees

Active traders often pay monthly for real-time exchange data, and some platforms charge inactivity or premium-tier fees. These don't show up on a per-trade basis but add up fast.

How to compare the true cost

1. Model your real activity. Ten trades a month in US stocks is a very different cost profile from daily futures trading.
2. Add the invisible costs: spread + FX + data + any subscription — not just commission.
3. Use the pro interface where one exists (crypto exchanges especially): it often cuts the spread/markup dramatically.
4. Check withdrawal terms: some platforms give a few free withdrawals, then charge.

We break these down on every review under "Fees & hidden costs explained," and you can filter the platform directory by the things that actually matter to you. If low cost is your priority, start with our best low-fee trading platforms.

Educational only — not financial advice.