Depends on whether the person wants to front the postage.

US Post Offices do not sell postage stamps for countries outside the US. For UK stamps, either try eBay, Royal Mail online (don't know if they'll ship overseas, though; I do know Canada Post will for Canadian stamps) or someone here.

US Post Offices also do not sell IRCs anymore.

Despite what some people may think, Global stamps sold in the US are good only for airmail letters _from_ the US. Some may gotten away with using them as stamps for a SASE. But the majority of times, Global US stamps cannot be used from countries outside the US.

So recently I sent off to Hayley Atwell in the UK. I included a SASE, however, I wasn't able to put postage as the post office workers told me they didn't have the UK stamps for sending back to the US.

What are the chances of getting a reply with no postage on the sase?

Thanks!