Sorry I missed this thread slip.
Is there a reason you want the flashlight afixed to the weapon? Because in that price range, it's going to be difficult to get a good quality one.
However, if you were willing to get a flashlight for off hand use, there are a ton of good brands out there for less than your budget.
As for lights that afix to your weapon, Surefire is by far the most promoted company out there. Their lights are very bright and their stuff is good quality, but it's expensive as hell.
Insight is a company that makes a good product. If you shop around, you MIGHT be able to find one in that price range, but it might be used.
This one is rated for your Glock, but all I know about the brand is that they are kind of hungry on the batteries if you know what I mean.
This will bump the post back up, so maybe someone else has a suggestion for you.