The cheapest stocks and shares ISA is not one platform. It is a different platform at £1,000 than at £250,000, and different again for funds than for shares — because flat fees win on big pots and percentage fees win on small ones. This is that answer, worked out for 13 pot sizes across 13 UK platforms.
| Pot | Cheapest for shares | Cheapest for funds |
|---|---|---|
| £1,000 | Freetrade £0.00 | Barclays Smart Investor £0.00 |
| £2,000 | Freetrade £0.00 | Barclays Smart Investor £0.00 |
| £5,000 | Freetrade £0.00 | Barclays Smart Investor £0.00 |
| £10,000 | Freetrade £0.00 | Barclays Smart Investor £0.00 |
| £20,000 | Freetrade £0.00 | Barclays Smart Investor £0.00 |
| £30,000 | Freetrade £0.00 | Barclays Smart Investor £0.00 |
| £50,000 | Freetrade £0.00 | Barclays Smart Investor £0.00 |
| £75,000 | Freetrade £0.00 | Barclays Smart Investor £0.00 |
| £100,000 | Freetrade £0.00 | Barclays Smart Investor £0.00 |
| £150,000 | Freetrade £0.00 | Barclays Smart Investor £0.00 |
| £200,000 | Freetrade £0.00 | Barclays Smart Investor £0.00 |
| £250,000 | Freetrade £0.00 | Barclays Smart Investor £0.00 |
| £500,000 | Freetrade £0.00 | Barclays Smart Investor £0.00 |
Every figure assumes 12 trades a year of £1,000 each, inside a stocks and shares ISA. It excludes Stamp duty at 0.5% on UK share purchases, the £1 PTM levy on orders over £10,000, fund manager charges (the OCF), and any foreign-exchange fee — every one of those is charged by someone other than the platform and is the same wherever you hold the money.
Because they are totals. A platform advertising "0.25%" is quoting custody only; a platform advertising "commission-free" is quoting dealing only. Cost is custody plus dealing plus the tier you land in, and no platform publishes that number because it depends on you. That is arithmetic, so it is done here rather than left to the reader.
Stamp duty at 0.5% on UK share purchases, the £1 PTM levy on orders over £10,000, fund manager charges (the OCF), and any foreign-exchange fee — every one of those is charged by someone other than the platform and is the same wherever you hold the money. And where a platform publishes a taper without publishing the rates inside it, the pots in that range are left blank and the platform is named with the reason on the page — never filled in with an estimate.
Charges read 19 August 2026 from each platform's own pricing page and quoted verbatim on the platform pages.
Charges read 19 August 2026 from each platform's own pricing page. Platforms reprice with little notice, and nothing here is advice — it is arithmetic on published charges.