What to expect for your budget…
This greatly depends on what your final purpose is. As technology gets better, cameras get smaller and capture more stunning detail with less bulk.
Setting realistic expectations
Depending on how old you are, you might remember Betacam SP cameras: the last of the great SD analog cameras. They could cost anywhere from 50,000 USD to 150,000 USD and up. Yes … this much for one analog SD (720x486) camera that needed a muscle-bound cameraman to carry it. Compare this to the modern DSLR cameras, and you realize that the gargantuan relic is nothing better than a doorstop today. The lesson: bigger is not always better.
If your goal is to carry a giant cinematic camera (such as a RED Scarlet), let me stop you right there. Even the DJI Spreading Wings S1000 (which, according to reports, has overcome all of the problems the S800 had)—a gargantuan octocopter that will run you upwards of 6,500 USD (without a radio or most of the other necessary accessories...