Once again thank you!! I really appreciate it.

Paper envelopes can go as letters which would be significantly cheaper. Those are priced by weight only:
£0.88 up to 10 g
£1.28 up to 20 g
£1.88 up to 40g

Photo mailers I am never sure if they will be classed as letters or small packets so i'd hate to advise either way and you not get your item back due to insufficient postage

As for US currency in foreign requests, personally I wouldn't do that but other members on here do it routinely and get items back.

Gotcha, thanks for the reply. So what about a 5x7 photo mailer? it's slightly thicker cardboard. If it's best to send just a 5x7 paper envelope, i'll get my hands on some of those.

Hypothetically, say I didn't have stamps and instead wanted to send money to make up for the lack of return postage. Someone i know asked me if American dollars will work for this purpose... i wasn't sure. It's really tough to get even euro where i live, and i can't imagine quid would be any easier. is it acceptable to send american money in foreign sendouts if you don't include stamps? it has to be easier to exchange us money in europe than it is to get euro money here!

An 8x10 bubble envelope is going to count as "small parcel" and any small parcels up to 100g to the US cost £3.50
Each 1st Class stamp is worth £0.60

In the UK generally celebs don't send 8x10s but 6x4s so you'd be fine with perhaps a 7x5 envelope (assuming you are not sending something to be signed).

A bubble mailer however will count as small parcel irrespective of size.

It's also a good idea to write "SMALL PACKET" on the top left hand corner of your package.

I apologize if this has been answered numerous times before, but I was looking to send a SASE to the uk for an autograph to give to a friend here as a gift in the states. I know what to do to get the envelope to the uk, but for the sase I just need to know how many 1st class english stamps i need. I have a book of 12 at my disposal I acquired online from Royalmail. I'm sending a big enough bubble mailer envelope for 8x10, so i'm sure it will be more than four 1st class uk stamps.

I'm not sure if an 8x10 mailer counts as a parcel or as a letter by their terms.

-ruk