If you don't have an Android phone with NFC, the N2 Elite with the official USB reader is probably your best option, but it will cost you around $80. PowerSaves for Amiibo (with the Powertag included, as not all of them have that) is the second best option, but you can only have one Amiibo at a time which makes it rather a pain in the ass.
If you do have an Android phone with NFC, then you can buy blank tags and easily write Amiibos to them using TagMo. This is my preferred option. 100 tags will only cost you around $35 and while you can only write one Amiibo to each (only the save data can be rewritten), 100 tags should last you forever unless you want to have every single Amiibo ever. Here's the link for the tags:
https://www.aliexpress.com/item/NTA...able-NFC-Adhesive-Labels-Dia/32315909847.html
N2 Elite can still be used with an Android phone with NFC, but it costs more than blank tags and is harder to manage multiple Amiibos with.
I wouldn't even consider the PowerSaves for Amiibo if you have an Android phone with NFC. It's cheap, but it's far too limited, and for only a little over twice that price, you can get an N2 Elite (without the USB reader) which holds up to 200 Amiibos at a time, vs the single Amiibo the PowerSaves powertag can hold.
So in short:
If you have an Android phone with NFC, buy blank NTAG215s, it's the best option. 100 of them for ~$35.
If you don't have an Android phone with NFC, buy a N2 Elite (with USB reader) for around $80.
Or if you are cheap and you don't care that you can only use 1 Amiibo at a time and need a PC to change to another Amiibo, get a PowerSaves for Amiibo that has an included Powertag.