Former GMRS WQGK720,Ham W2ERD. My GMRS repeater was and still is a Motorola Desktrac UHF, the nice thing about these repeaters is that they have thier own power supply and fan and in my case it run 24/7. They can be purchased off Ebay for about $350 to $500 and if you know a Ham operator he may have the software to program it . You can use a mobile duplexer which you can be purchase from China for about $50 or less , they even will tune it to your, or you can us two UHF antennas one TX and the other for RX. With any radio system you need a good UHF antenna,and a short run of LMR-400 coax with N-connectors if possible and you need to get in up high. My system when it was on line would cover about 25 or more miles at 28 watts . When it come time to renew my GMRS licenses it would have cost me $200 and because my repeater got very little use I let go.
Because of the narrow banding a lot of good Motorola radios are up for sale. I have four 900Mhz repeaters running 24/7 now all using Motorola radios.
If you need programming and are willing tp pay the postage both ways I can help you.
Just checked on the GMRS license renewal its $85 for five years..not $200, sorry..