I've never treated 1,2 and 5 seriously. Ethereum might still be a good investment and maybe now is a good time to buy it for $300. I guess one can wait a bit and the price will drop a bit more. As for NEO - it's sad but true that this coin is totally crushed and is not likely to become great again. People mostly buy altcoins for btc or eth, but there are big exchangers with usd markets as well. Try bittrex. It's one of the biggest and most trusted markets out there. You'll see the USD option there as well. The only big con of this one is that they have a small max withdraw per day. I don't remember it right now and it only matters if you are a big playerm the the amount is something like 0.1 or so.