I really would like to start watching how I play. I think some video feedback can help anyone's game dramatically. Who knows what camera's and mounts work well with the sport of paintball? Obviously the cheaper the package the better.
If you don't plan to make them into youtube highlight videos and just need video to reference for yourself, you could go really, really, cheap like under $20. There is a md80 camera it's a small clip on type camera that is surprisingly more than OK quality. You could mount it inside your goggles like in this video.
Using this camera instead of the keychain one in that video.
I bought one for a friend who wanted to take video, got it for $8 on ebay and it actually turned out fine for him. I don't have the video to upload but there are youtube videos if you search md80 paintball, just know the quality drops down once uploaded.
From there you could step up a bit and go with something cheap like a Drift HD720, I have picked up a few of these on ebay for other people and projects, some refurbished and some used but working, for about $40-$45. They attach to a mount that fits any strap on a mask which you can then zip tie or epoxy for a stronger fit. Or a handlebar mount that you can attach to the barrel. It's an action camera so it takes a hit fine.
This is a more expensive version, the Drift Ghost, but the same mounting applies for the HD720.
From there I think the Contour or the Ion Air Pro are the next step up. Same general principle for mounting as the Drift just a more round tube style that probably offers some easier mounting options.
The top of the food chain is probably the GoPro obviously, and the price reflects it. Although there is a knock off version that people have given good reviews about, it's called the SJ4000, but it's still in the upper 90's into the low 100's so you would have to figure out if it's worth the risk.
There is the R7 but I have zero experience with it besides some youtube videos which take away from the quality it could be, so it would be unfair to judge it.
As far as mounts go, usually the hardware the camera comes in is fine, you might just need to use some epoxy to secure a good fit to a mask. For a barrel mount, any handlebar mount would work.