What type of lemos are you looking for?
I have found a lot of lemos on ebay for super cheap. I recently got 6 FGG.0B.302 (the bartech power size) for 30 bucks and 5 FGG.2B.306 (red one power cable) for 25.
as long as you know what you are looking for, you can find some good deals.
As far as the battery plate, it is possible, but unless you are really comfortable working with wiring and DC current, I am not sure I would recommend it.