Karting??..

No problem. I won't ever use it, but I'm not even sure if I have one anymore.
Neck Braces
Here are some that are quite a bit cheaper than a hundred bucks. I would double check and make sure they are legal in your class, but I wouldn't see why not.

Our club required the neck braces many year ago. I have a Simpson. The foam inside can be trimmed to make them more comfortable if need be without sacrificing the intended purpose. Leather MX gloves work well. I had a race suit long ago because it was a part of the deal for the kart. When I went dirt trackin' Carhartt Bibs of the Duck material served me well with a sport bike type jacket over it.