I listed some places you can get them in my previous reply.

brilliant ok, where do i get the $1 bills from? I thought maybe eBay but they could be fake ones...

If you can't get stamps then try getting currency. The US handily do $1 bills you could send 2-3. Try the Post Office, a Bank or a Travel Agency. The IRC is no more and there is no replacement. So the alternatives are stamps or currency.

http://www.usps.com has a price calculator which will let you calculate the return postage price. Prices start at $1.15 for a one ounce envelope to the UK

hi, I have made posts similar to this before but still need help.
I tried getting U.S. stamps from the USPS website, only to find they don't post them to UK. I tried their internationally posting eBay store, only to find that, obviously, the postage price was larger than I'd anticipated. Also they only sold them in large quantities, I'd only want maybe 4 or 5. Is there a UK equivalent to the no-longer-sold-in-UK I.R.C.?
Also, if I did get hold of US stamps, how many do i put on my SASE?

thanks so much and best wishes,
ufanmail_29 ;)