Exchanging US for UK pounds is super easy. There are exchanges on every street in London, but it will depend if the celebrity wants to take the time to that. I've luck with sending US dollars just remember that pounds are worth a lot more so you send $3-4 for a 4x6 and more for an 8-10. If you want to send pounds you can them at almost any bank (as long as you have an account). It takes a few days, but they can get you any currency.

If you want to get stamps, try to trade on here. The ones on ebay are ridiculously priced.

Hi I live in the USA and I want to send to the UK however I heard post offices no longer carry international reply coupons, so should I send USA dollars? if so how many? also how would sending USA money to the UK work? will the celebrity use it towards stamps or is there a way to convert the dollars to their currency??? I'm so confused how that works, I thought USA currency is useless internationally