Look in the Radio Models wiki for information about digital trunk-tracking scanners.
Categoryigital Scanners - The RadioReference Wiki
You'll want to look at one of the more recent digital models, since York Co operates a Simulcast P25 system. No scanners are perfect at monitoring these systems but newer models are better at it than older models. Some of the older digital models can decode APCO-25 voice but can't track the 9600bps control channel, so make sure to pick a model that fully supports APCO-25 trunktracking.
Keep in mind that while GRE-made scanners can still be found new (mainly in some RadioShack stores), GRE is no longer in business. Repair service is only available via 3rd parties and parts are scarce at best, and more commonly completely unavailable.
Whistler is reported to have purchased the rights to GRE scanners and may begin remanufacturing some of the GRE models in 2014. Time will tell.
None of these newer digital scanner models are "cheap" by my definition. Ebay, Craigslist and the RR Classifieds are good places to look for used models, but you probably won't find many bargains at this time. If you can wait 6 months or so, the availability of the newest Uniden models plus the possible entry of new Whistler models to the market may glut the used market with current models and drive prices down. Now may be a bad time to invest in a digital scanner.