What are /r/ACNH_FAQ's favorite Products & Services?

From 3.5 billion Reddit comments

I don't know where you live so I can't recommend specific stores, but I assume any that sell merch or electronics in general may have them. You can also buy them online on the official site (linked below), Amazon or eBay.

The official site lists all cards. If you're looking for specific villagers, make sure you buy the correct series! For example, Roald is in series 1. So if you want a chance at getting his card, you need to buy series 1 packages (the green ones).