If its cheap and thats all you can afford than it could be worth buying. Just remember that they are no longer supported by GoPro and there is limited support through any other means. It will have all of the known issues of a GoPro Karma and s time passes there will be fewer and fewer second hand parts available.
Personally I think you would be better off getting a second hand DJI, that said I like Ironspear still have a Karma and its flying well. I have stock piled a few replacement parts too.