Wanenmacher's mega-show (Tulsa, OK) charges $10 at the door. Parking was free when I went, but that was 15 years ago. No idea if that's still the case. Even if you paid a few bucks to park it's worth it. Advertised at 4200 tables. If someone there doesn't have what you're looking for, no one will. Friggin incredible show.
We have two different local shows. The smaller one (fairgrounds) is $5, the larger (Civic Center) is $8. Free parking for both. Even with that, both verge on being overpriced given the dearth of actual firearms-related vendors. On the flip side there is a great selection of fudge, candy, beef jerky, and essential oils.
Brad