Today, options are somewhat limited in terms of "new" digital trunk-tracking models. Uniden has the BCD436HP amd BCD536HP models, which are their "lastest and greatest." Uniden also has the HP-1 (with its characteristic touch screen interface) and the BCD396XT and BCD996XT. I believe that all 5 of these models can be purchased new at this time.
The other manufacturer of digital scanners is in transition right now. The former manufacturer, GRE, is no longer in business. Whistler (of radar detector fame) is reported to release rebranded radios based on the older GRE designs within the next few months, but they are not available today.. A few "new" PRO-106 and PRO-197 models might still be found in some RadioShack stores (if your local store isn't closed). Otherwise these two models, along with their GRE-branded PSR-500 and PSR-600 cousins, can be found on the used market. GRE also made the PSR-800 but it is only available used and typically at a very inflated price.
Olders digital trunktracking scanners (like the PRO-96 as an example) are not recommended.
You would do well to perform a good bit of research before you jump into this purchase. Take time to understand what features are important to you, and know what additional accessories (programming cables, programming software, antennas, power supplies, batteries and chargers, a subscription to this website, etc) are required to accomplish what you expect to accomplish.The wiki and model forums on this website are excellent resources.
Also take note that the type of system used by North Charleston (a P25 simulcast trunked system) can be troublesome for consumer-grade scanners to receive well. You'll read lots of posts on this forum by users that have trouble monitoring this type of system with any and all of the radios listed above. Many posts are contradictory. It all comes down to your location and type of antenna used.
Brian's well thought out and thorough response is excellent, as usual...
The only thing I can think to add is that I have had an overall excellent experience monitoring North Charleston with the Uniden HomePatrol (HP-1). It has a very sensitive receiver, and the touch screen interface tends to make it more "wife friendly", should she decide she wants to operate the darn thing herself.
Based on reports from early adopters, it looks like the jury is still out on the two newest Uniden BCDx36HP models. Overall, they look like good radios, but there are stupid little things that people are having problems with. For example, dust accumulating behind the display screen on the handheld, and a headphone issue and delays in releasing features on the mobile model is a real charlie foxtrot. Personally, I'm holding off until some of these issues are resolved before investing my hard earned money.