You get what you pay for. Handguns have a lot of recoil for electronics. EVERY time I see someone who thinks they are smarter than everyone else, and they buy a cheap laser - they discover that the thing either flies off the gun all the time and/or does not hold zero at all.
The Lasermax Unimax, or the even smaller version of that from Lasermax that just came out is probably the cheapest way to go, if ya don't want to pay for CTC grips or a laser guiderod. They are t just over $150.