big reds go for around $350-600 unrestored, but in good condition. There isn't really a reason to target a fully restored neogeo unless you absolutely can't
with a bit of CPO damage and some wear on the corners. I can't say I have ever seen a 'restored' neogeo for sale but if i had to guess its going to be above $1k.
The games are another mess entirely. Some games are as common as a bird turd. Games like king of fighters, world heros go for under $20-30. Games like metal slug are usually $50+. Moving into more rare games like neo drift out, bomberman, windjammers you are going to be looking $120+. Nightmare in the dark, magician lord can be $300+ when they come around depending on who's looking. These are just for loose carts. Add about double to the price for a complete kit.