That's a great, and very generous, idea! I worry, though, that if I can't order product, I won't be able to buy a gift certificate, either - unless you meant from somewhere else. I'm a Norwegian-American (American citizen) living in Norway (resident), so I have debit cards from either country and should be able to easily order product or gift certificates from most places in the US and Europe.
I can't remember the names of the pdfs, but they were #2-4 of the one-shot Starfinder games. I have too many migraine days to be a reliable, weekly GM, but I like to always have a one-shot ready in Foundry for the days when our regular GMs (my husband, and a friend of ours) are too busy to run our normal games.