Are you looking for something simple, portable, and plug n play like a USB mic, or the option for more simultaneous channels and possibly better sound quality, but less portability? There's a few different USB mics out there that'll work as well as any for simple recreational recording, but with microphones (and almost anything in our niche) it tends to be you get what you pay for. $250 is fine for budget recording as long as you know your expectations. Also remember that it's largely up to the person recording. A professional engineer can make a professional sounding recording with budget gear but an amateur with professional gear can make a big mess.
For a nice simple USB mic you can check out the Shure SM57 + X2u adapter.
http://www.shure.com/americas/products/ ... tal-bundle
Shure also makes a USB condenser mic that depending on your needs may work better for you. It's $250 so right at your goal. Audio Technica, Samson, Blue, and many others make decent USB mics as well. On top of that you'll need a mic stand and that's about it.
If you want an interface you can check out Avid, Focusrite, M Audio, Presonus... At your price range you'll be able to get 1, maybe 2 XLR inputs and normally a 1/4" input as well, so you should be able to do 1-4 tracks simultaneously depending on what you get. If you go this route you'll still need a mic, mic cables, and mic stand so right there you're looking at another $100+ for bottom line gear. You can get all this under $250 as well but it's going to very limited and won't have the greatest sound quality.
You're also going to need some sort of recording software. Garageband is pretty basic (and free) but is perfectly fine for most likely anything you'll need. I've been using Garageband exclusively for the last year or so, because at the moment that's all I need. Whenever I get myself a nice interface again I'll upgrade to something better but for demos, scratch tracks, or just capturing riffs it couldn't be easier. And if needed it's absolutely possible to do a full band professional mix in Garageband. Won't be as easy and doesn't have as many useful tools as better software but it most certainly will work.
