Degiro is less: 0.10%. They also provide an alternative of manual conversion from a multicurrency account at cost of 0.02% + €10.
Compare buy 1 share Amazon.
Old T212: $3150
New T212: (0.15%) $3150 + $4.72
Degiro: (0.10% + fee) $3150 + $3.15 + ÂŁ0.49
Of course Degiro does not provide the option to purchase fractional shares.
Currency conversion fees are not allowable costs when computing capital gains.
So far as I can tell Interactive Brokers charges 0.20 basis point, ie 0.002%, with a minimum charge of $2. So a round trip from GBP to $10000 USD and then back to GBP costs about $4.40. Whereas 0.15% costs $30. Trades with Trading 212 are free, whereas on Interactive Brokers 40 FB (cost about $10k) would be around $0.35 to buy and $0.35 to sell, which is deductible against the monthly fee of $10 (or $20).