I use Gunbroker also as a reference for prices of gun. I have noticed in the past few months, that on common guns, cheaper price can be had locally even after factoring the 8.25% sales tax here in Houston.
I had a conversation on this matter with a guy who is both a member of my range and a gun dealer, and he admited that he has re-adjusted his prices to reflect the new reality of Gunbroker.
Also prices have been rising pretty fast on GB in the past month. I don't know if it's the Obama thing or bump before Christmas. Just something else to think about.
Experience is a very bad teacher because it first gives you the test and then teaches you the lesson.