Amiibo cards help.

Yeah, I'd look for the amiibo festival cards on ebay as well, you can get Stitches for around $7 usually, and sometimes less! As for Merengue and Marshal, my recommendation is to check all of the listing that have deals if you buy multiple and see if you can get a discount, check all the ones with tons listed in a dropdown menu because usually the prices for cards are cheaper on those than listing that are just one individual card. I hope that makes sense!! Not sure I explained it too well, but basically some people have like buy one get one free deals and if they have multiple cards you need it would work out really well! Good luck!

Well I would continue to check because eBay has stitches for as low as 10 dollars right now and merengue 15 dollars. But, like others have said, you can try you luck at trading cards on the post office here or reddit.