You can get into HF amateur radio for 100 bucks these days. Checkout this kit form QRPlabs http://shop.qrp-labs.com/qmx
Discussion
What can I do with this?
I have a QCX and a QCX Mini from them. If you ever wanted to try a radio kit, this is the one. Great parts, great instructions. Be anal retentive for best results.
I have a 40 m QCX+ and a 20 m QCX Mini. They both work well and were fun to build. I also have a QDX that I need to build. QRP labs have great designs, so I expect the QMX to be a good choice.
I presume you need a big antenna of some sort to use with this?
Here's the history behind it.