Honestly? eBay...there are great deals out there. I just won 5 Trident Chevy's and a Busch Ford for $22. Trident's are great because they're easy to work with and customize.
The top one resembles airport security/maintenance where I live in New Hampshire. The second one I was going for a volunteer firefighter's Chevy Suburban. Where I live there really any full-time fire departments.