Just looking through ebay I see a few with a buy-it-now price at 650 Canadian pesos, but more than a few other sellers offering it for the original 1500$ price. 900 new seems to be the going rate for the majority, and it shouldn’t be too hard to find for 700, but for the 300$ range you’re looking at buying a damaged used thing and cheaping out on parts trying to fix it.
There are RTF foamie models available in that price range, but it’ll be a full manual deal, probabaly with a cheaper camera and no autonomy/programmability like C.H.U.C.K. provides.
Here’s a ready to fly stick model for 60$ if you just want to fly something plane style on the cheap:
The Von Stik - Micro Slow Stick (Mode 2)
hobbyking.com
There’s also simulation programs that come with a usb controller like an rc controller, you can use that to pratice and try out different control setups to fly rc helicopters, planes, gliders and the like. they do FPV modes too.
I use RealFlight.
RealFlight RC Flight Simulator