You can only write a cheque in dollars if the account actually holds dollars. I would assume that you are asking if you write the cheque from your UK account. Assuming that your account is in pounds, you would only be able to send a money order from your account. Essentially the charge for something like this is about �10 (even for an electronic transfer) so that is how the price is 'doubled'. The only way I can think you could get around this is if someone in the US writes a cheque on your behalf. You can then possibly use Paypal to send it to them.