I found out about custom amiibo cards the other day (I actually ended up buying some Sanrio ones, just from a different seller though, since they were cheaper and the ones linked don't ship to my country) and I think they're ingenious!
I'm definitely not going to shell out $60+ to scalpers just for a few paper cards, and honestly, with the amount of money Nintendo makes, I don't exactly think handmade amiibo cards will really hurt them; especially since you can only really get them second-hand nowadays, and I'm pretty sure Nintendo is trying to phase them out anyways.
@ OP, I think handmade amiibo cards are always a really good option if you're desperate to get Sanrio villagers but can't afford to shell out the cash for official ones