You might consider the Hitec Optic 6 radio. It is 2.4 ghz, but can be converted to 72mhz with a module. The 72mhz recievers are less expensive than 2.4 but still work fine as long as the people at your flying site don't turn on their radios without checking the frequency board. If you really want to go with low cost equipment, just buy a used 72mhz radio on a site like this. They are still good performing systems from major manufacturers and most are selling for about 1/2 what they cost new, some even lower.