RE: Need inexpensive setup...
I was wondering why you would want to rescue planes after they have been lost for months? I found a couple lost planes. After a few months, the planes absorb moisture and weigh about 3 times as much as before they crashed. Some electronics might be reusable.
There really isn't any cheap viable system out there. Buy cheap and you'll buy twice or even three times. Nonetheless, getting a system fully functional is sometimes difficult which costs more money. Hundred dollars here and there, before you know it... you'll have over a grand in your plane. My Vidfly cost about a grand considering all the upgrades, changes, mounts, connections, batteries schemes, isolation issues etc... The list goes on. It's one thing to purchase a turnkey video solution, but to make it work in a plane is another. I don't want to discourage you, but you should know it will cost more than a couple of hundred dollars, then add some luck implementing the hardware and hope you don't destroy the equipment on hard landings. The most expensive thing will be your experience and time to work out the buggs. These items must be figured in.
A another thing to consider. Each time I fly without the video... no problem, it's easy for me. But, when I fly with video being captured... it's a hold different world. I get nervous and find the flights are not nearly as smooth as without video. Unless you have a truly multipathing brain ofcourse-grin. Good ground preparations and flight plans will help take out some of the uncertainty.
Good luck with your project.
Rob