Are there any mobile 2m radios with aprs functionality that are, uh, CHEAP? I'm looking to get into aprs, but don't want to spend $300+ for a radio (especially since I doubt I'd ever need 70cm, and they all seem to be dual band). Or am I missing something (just got my ticket a week ago, so I'm really wet behind the ears).
Built-in APRS is a premium feature, so it'll be difficult to find a "cheap" radio that includes APRS. Don't let that discourage you though, there are other ways.
* Generally the lowest cost way to get into APRS is to find an old Windows PC (anything from XP on will do) and download UI-View. That will handle the APRS software part of the equation for you. The software is free (but you'll need to register it, also free). The PC is probably in your old computer stash but if not, ask around since your friend probably has one they'll be happy to donate to you just to get it off their hands.
* Next, find an old, but working 2 meter radio (a mobile radio is probably better, but you'll need a power supply with enough power for the radio during transmit and antenna, but nothing too fancy). You could use a handheld, but chances are that old handheld will need a new battery and that alone will exceed the cost for the much better used mobile radio). This radio doesn't need to be feature full, a single band 2 meter radio is fine, it doesn't even need to have PL Tone functionality!
* Next, find a working packet TNC (doesn't need much beyond the KISS standard so nearly anyone will work here). You could also download a "Soundcard TNC" that uses your computer's soundcard to act as the TNC, but there's a catch. You'll probably need to build an interface between your RS-232 serial port and the radio to handle the PTT functionality. This isn't expensive, but requires a bit of skill (minimal, but still). An old used, but workable, TNC is probably cheaper if you look (the last one I got was only $5) and easier to set up and operate.
If you must get everything on your own, and do a bit of hunting (a local hamfest is a good place to start), most can be found for next to nothing. Asking for help at a local ham club could cut this down to zero, or perhaps a few bucks for some cables since most repeaters need PL and many hams no longer need their old hardware TNC since they upgraded to those new dual band radios with built-in APRS.
My setup uses an old PC (from my junk stash) running UI-View. My dedicated radio is a very old Azden 2 meter radio (from my old, long since upgraded radio stash). My dedicated APRS TNC is that $5 special I found at a hamfest (had I waited until the seller was about to leave, it probably would've been free, but I digress).