300-400 bucks is tough to do. I see you're fairly close to a lot of repeaters for 2M/440. 10-18 miles from Luling. You could probably hit the 2M ones with a HT and J Pole. Or you can get a decent mobile antenna with some gain for your vehicle. The Baofeng UV-5R can be had for about 38 bucks shipped to your front door. Easy to program with Chirp (free program), but you'll need the cable to hook it up to your computer. They run about 10 bucks on the internet, or again... borrow one from another ham. You might find a club member that would even give you an old mag mount mobile antenna or a J pole for the house. Get an adapter for the HT and you're on the air for less than 50 bucks. I'd lean more towards a used HF rig than an export radio, unless you come across a killer deal on a President or Ranger. The Yaesu FT-747 and Kenwood TS-430S usually fall into the 350 or less price range. Make a dipole for 10 meters out of whatever wire you have sitting around, or use an extension cord (HomerBB described how somewhere on the antenna forum). Next problem is a power supply... but I'm assuming since you've been a CB'er that you already have one. A good 20-30 amp one will run an HF rig. 10 meters has been HOT, and contacts into Europe seem to be pretty easy right now.
Best of luck, and let us know how you make out!
73,
RT307
