Depending on your technical knowledge there are several options. A company called Bridgecom builds a "turn-key" Part 95A repeater. Just needs the antenna side figured out (separate versus duplexer). Icom makes a NXDN/analog repeater on a mobile chassis that is in the $800 range (no power supply, duplexer, etc) last I checked and I believe it is only Part 90 accepted. If you want to get technical, you could take something like a Hamtronics R300 series receiver, a surplus mobile radio and tone controller and build a nice little repeater for around $600 and you'd be able to get away with a mobile duplexer setup (even in a fairly high noise environment) for another $100 and spend the rest on feedline and antenna. Or you could do the strap two mobiles together method and approach other factors accordingly.