Well, if it's for the express purpose of listening to the Charleston Co. P-25 system, then you might want to do some research before you buy. The PRO-96 and PSR-500 are not particularly good at decoding the digital audio format used on this particular type of system (Motorola P-25 simulcast system). I have not tested nor have I heard any first-hand accounts of anyone using the newer Uniden digital scanners with this system, but in general folks have had disappointing results.
You might consider the PRO-106 from RadioShack. It's identical in function to the PSR-500, and it's on sale right not for $399. RadioShack offers a 30-day return policy, so you could purchase it and try it out, and then return it if it doesn't suit you.
Some say using a directional antenna pointed at the strongest local tower site helps, and that might be true. But I haven't heard of anyone testing that theory on the Charleston P-25 system.