A dealing charge is a fixed fee a broker takes each time you buy or sell. Because it's fixed, it's a bigger share of a small trade: £10 is 10% of a £100 purchase and 0.1% of a £10,000 one. Many platforms offer regular investing — a set amount bought on a set date each month — at a lower charge, sometimes none, and some charge nothing to deal in funds.
It's the number of trades that adds up. £100 a month at £10 a trade is £120 a year in charges, a tenth of the £1,200 invested; the same £1,200 bought at once costs £10. The dealing charge is only part of the trading cost: the spread, stamp duty on UK shares and a currency fee on foreign ones can come on top, and brokers offering commission-free dealing often earn from those instead. The app has no fee field, so to count a charge in your cost basis, add it to the purchase's total cost.
An illustrative charge. The same £1,200 in a single purchase would cost £10.
Educational content only. It is not personal financial advice.