Good banjo guitars are very useful for finger-picking, ragtime style, but not for much else. Johnny St. Cyr played one on several Louis Armstrong Hot Five recordings, when he wasn't playing tenor banjo, but not many other recordings seem to have been made till Sam McGhee's work with Uncle Dave.

Now, Sam played a Gibson, and it rocked. But a Dean isn't a Gibson, and it isn't even a Stelling, the one company I've heard of making a real quality instrument these days. The cheapest Stellings are around $900 or so (street price, not list). Someone mentioned Odes, above, and those are probably good 'uns, but most likely priced like Stellings.

I've seen Deans for lots less than the price mentioned in the original post, above, but I'd play it a lot before buying, if 'twere me. I got a guitar banjo online, used, but didn't pay that much for it. It's a Goldtone, and I understand they now make a second model, better than the one I got. If you're really interested in playing guitar banjo, look for many makes and models.

If you just want the banjo sound but only want to play guitar, well, be advised that you get what you pay for (in both money and effort learning the instrument).

Bob