I'll try and answer all your questions, via this entire thread, in this one post. And maybe give some extra info? I don't, this might turn into a wall of text. I'll do my best to not do that.
I own pretty much every possible way to make spoofed amiibos. From cards, to coins, to the PowerSaves (find it at GameStops), and also the N2 Elite.
Cheaper Alternatives?
The cheapest way to make amiibos is, and will probably always "stickers". It is a round sticker, you zap it with an Android device, stick it on something (like a piece of paper), label it. Bam done. **You can buy and do more that increase the price here, but even still it is the cheapest path.
The next on the list from cheapest to cost the most is NFC tags. With both tags and stickers, make sure they are the right type. Zappy the card like the sticker, label, done. **Like the sticker, you can go on to make custom cards.
PowerSaves . This is something you can find from Datel. You want whatever package comes with the USB portal. This is how you load the puk via PC. So...you need a PC. The puk can only "be" one amiibo at a time. Via the program that you install, you can change it as you need...again with PC. The PowerSaves should not cost more then $30. The downside is the puk will burn out. How soon? No idea. You might get over 100 uses, or you might get 10. GameStop seems to know about this, and from what I've heard, will replace if you return. You can also buy extra puks, I've seen them on eBay. They range from cheap to cheap.
That brings us to the N2. If you really want to go this way, there are 2 options: Just the N2 puk, or the N2 puk and the USB portal device that connects to a PC. You technically can use an android phone to load the puk, I just found it to be too slow for my liking. So I bought the portal. The package deal on this is around 80$. The pro: You can have a lot of amiibos on this (like 200). The con: You need to print of a list of the amiibos. You have to cycle through them each time you want to go from a certain one to the next. You do not have to have the puk full. So if you only have say 5 on there, it only cycles them 5.
The PC program vs phone for the n2 is just... I can load the n2 much faster with the PC. I can make a list, and it is loaded in just seconds. With my phone, I have to add one at a time, navigating to the bins each time. Takes to long. I only use my phone to add 1, when checking bins.
You asked if there was a battery in the n2. There is not from what I can remember when mine fell apart. Just like there is no battery in amiibos. How does it know what one to be on? Don't know, that is the magic of the N2.
Buy it off Wish? That is a big dice roll. If you do, let us know how it works out. I'd not take the chance. There isn't much inside the puk, so you saving a ton of money might just end with you getting an empty puk :3
What should you really do? If you are asking us...well... do you have an android phone that can write NFC? If so, I'd go with making NFC stickers. Get as many stickers as you will need (I have bought these exact ones, from this seller, many times now) and get this coin saver and case . I have an entire set where I zapped the sticker, stuck in inside the coin, and just wrote what it was on the blank side. The added case keeps them in check.
I use my N2 now just to check bins (as I said), if it works right, I make a coin.
Back when I played Zelda, I used the N2 a lot more, because you can also create copies of amiibos, that the game would read each use. So ... I did at one time have 200 "different" Guardian amiibos to gain a toooooooon of arrows :P
If you have more questions, asks. I'll do my best.
Seems there are a few peeps asking the almost the same questions :p
Here is what I suggest:
1) These tags
3) And this hole punch (or one similar, 1inch gives wiggle room, the coin case only has 30mm of "open" space. The NFC sticker is about 28mm wide).
As for a hole punched into the ...tag? As long as you don't damage the chip I would think everything would be fine.
Here are some of my current coins by the way. I just lack a hole punch, and really don't feel like cutting out small circles.