A $30 RTLSDR actually does a reasonable job of receiving. I measured one at 0.1 uV sensitivity, which is surprising given the fact that the samples coming out of it are 8 bits of I/Q data. If you're trying to receive low bandwidth signals, such as AM/FM radio, SBB, Packet, etc... they're actually fit for purpose.
The FPGA based transceivers are out of my price range at the moment. If I were to dive into that field, I'd be using something with at least 8 channels, to do passive radar, and things of that manner.