Can I, as a Canadian buy an online gift card to give to my gf?

Hi! I'm from ontario, my gf is from colorado and her birthday is coming up so I want to get her an online gift card for $20 USD (cause shipping a present takes far too long lol). I'm worried about the money transfer not working, or if I buy it using a billing address in canada or a canadian credit card it either wont go through, or the gift card wont function. does anyone know if it'll work? thanks!