What about a blade tech 5.11 thumb drive holster? I beat the crude outta mine no issues other then sanding abit of the inside to get a smoother draw was a wee bit tight at first and I like the no resistance feel now. I've run it in sand, rocks, water, and mud all combined no issues with it working.
http://www.blade-tech.com/5.11-Thumb...r-pr-1274.html
Can be had for under your budget.
I also took my thumb guard off as I found with my gloves it slightly caught them. Even with that being said I've tested someone seriously trying to take my sidearm from me and he was unable to.