I strongly dislike elbow pads for shooting as I think they make you too unstable in the prone and are too restrictive on arm movement. I usually just accept the discomfort.
That said I was recently training for a competition that included a stage with 10 exposures at 200 - 300m, spread over nearly 8 minutes, from the prone, on tarmac. After rehearsing it a few times and with my kneepads in mind, I bought some velcro and neoprene elbow wraps for sports/weights and put them on loosely. Something like this:
I am a convert. They offer enough protection to make me comfortable and restrict my movement little enough to be tolerable. I still would not wear a full elbow pad though.