If you can, try to get a pad charging cable that's Nintendo brand or pumps out enough power as the Nintendo charger.
When I bought my Wii U off eBay for a good price (like $70 or something like that as the person didn't know if it workled except for what his kids said), it didn't have the pad charger. i bought a third party charger which charged the pad fine BUT the pad had a crap battery. I tried playing the pad while the charger was plugged into it but the charger got pistol hot after a half hour. The Nintendo brand charger pumps out more juice so you can play your pad plugged in. Unfortunately I can't find good Wii U pad batteries so that's how we gotta play the pad.
I got a bare NES deck from someone at Atari Age for about $30 shipped and here's the story why I got another one. My wife owns a two family home that she rents out with the upstairs being an Air BnB. The past tenants left a lot of stuff behind when they blew town (and messed the place up bad like drilling a like thirty industrial screws into the wall to hold stone mini knick-knack shelves) and that prompted her to not deal with such folks again. So from this we had a 55" plasma and stand to use along with small appliances and she decked the place out with old 70's style furniture as it was the least expensive. Nice stuff, don't get me wrong, but very 70's (dark brown and green recliners, yellow, brown and white afghans, etc.). We also don't have cable TV or even streaming, just regular WiFi, a DVD player, a VCR and some DVDs and tapes. She got a lot of comments, usually sarcastic, as to how much a "throw back" the place was. For as inexpensive as she charges, you'd think people wouldn't mind but many want all the modern conveniences but not want to pay for it.
Anyhoo....I said to my wife "well, why not MAKE the place truly retro? Advertise that as a feature to "disconnect"" but she waved it off. Recently she got reviews stating how much a couple guests LIKED how the place was-not streaming TV, they got to use a VCR for the first time in 20 years...and she said "you know, that might not be a bad idea". So the NES is going to go into the AirBnB (as I don't want to put the NES I have had since a teen) and right now I'm on the prowl for a 27" CRT.
On the "for kicks"side of things, I saw a 5" black-and-white Emerson portable TV/Radio at Goodwill for $8. It has antenna hook ups so I envisioned playing some Atari on it....so I got it.