I have about 20 Amiibo cards in total. I have 10 regular villager cards. The first one I purchased was Grizzly because he's my favorite villager and I really wanted to move him into my town. Later, I also purchased Anicotti's card because she's my second favorite and I decided I really wanted to add her as well. Grizzly and Anicotti are my only 2 Amiibo villagers in my main town, Sakura. The rest are random move-ins or were invited from my campsite and I plan to keep it that way. I like to cycle through random villagers every now and then to see who I get and meet villagers that I maybe never would have gone out of my way to get.
The other 8 villagers cards are ones I purchased for my second town, Nocturne. It is going to be a themed town so I wanted specific villagers. I already have 2 of the villagers I want living in Sakura, so I'll just move them over to Nocturne when the time is right, but I went ahead and purchased cards for the remaining 8 villagers so I didn't have to stress about anything. Most of the villagers I wanted aren't popular so their cards were really cheap.
I also have about 10 of the Welcome Amiibo RV cards that I purchased in order to buy furniture for my two towns. I thought about doing trades on here for the items I needed, but trading and interacting with other people really stresses me out so I feel better having the cards on hand. Plus, now I have access to as much of the furniture whenever I want. I don't have to worry about what to do if I decide I want something later after New Horizons has come out and everybody has moved on to that game while I'm still playing New Leaf. I did spend more than I probably should have on the WA cards because I bought them separately on eBay, but that was the only way I could find the legit cards and I decided I didn't want knock-offs (no judgment towards people who go that route, it just wasn't what I wanted to do).
I don't have any Animal Crossing Amiibo figures, but my husband collects Amiibos just for the sake of collecting them so I have access to all of his Legend of Zelda Amiibos. But he likes to keep them in the package and I'm pretty sure I can't scan them that way, so I guess I'm out of luck if I actually wanted to use one.
I have 2 of the older 3DS's so I did have to buy an NFC reader. I was lucky to find one on the Nintendo Store website for only about $20. I've heard of people having to pay much more.
As far as a favorite Amiibo, I don't know. Maybe Wade the penguin. His was one of the first WA Amiibo cards that I bought. I love the furniture in his RV and he is just plain adorable.
