Does anyone have advice on how to get UK postage to put on some self addressed return mail to the USA? I've researched this online and can't seem to find anywhere that will sell and mail them to me in the US, and I don't think I know anyone currently in the UK I could ask.

I've also inquired with the USPS and UPS already.

Any advice on that or getting any sort of prepaid postage to include on an autograph request would be appreciated!

Thanks in advance.