Honestly, I think most DVD players have them these days. For that matter, many TVs also have a USB port on the back which supports playback, but that varies a lot more between models.
They do exist. As for deals, I cant help you there, maybe a second hand store
Try your tv if you have one already. My flat screen tv has a USB port, the only issue is it only reads a few levels deep so if the folders or files are nested too deep, they might need to be moved so they are only 1-2 levels deep
Yeah, no problem. I have 3 of these Samsung BD-J5700 players. Found 2 of them at thrift stores, cheap. At one time, I had a hard drive I just left plugged into it with a bunch of shows and downloaded YouTube videos. It worked great. Now, I just have a PC plugged in and my players are just collecting dust. But if you can find one of these, they work great for playing off USB.



