A couple of months back I posted a video about a cheap little receiver I'd bought, FS2A 4CH AFHDS 2A Mini Compatible Receiver . Just around £6 delivered. The only downside is you have to solder the connector pins to the tiny little board. Soooo, here's a video showing how to do it and also how to bind it to a FlySky receiver. They are great for small lightweight builds, I've used a few of them and never had any issues with range. Another upside is they will even work with a 1s lipo.
aliexpress link is in the video description
aliexpress link is in the video description