I would avoid them eBay ones, had loads of them fail with a few LEDs on each lamp failing and they don't give out the right sort of light, they are more for decorative lighting more than anything and I would still be hesitant to use them for that.
Unfortunately to light the room properly with LEDs you need to spend then money.
As for transformers most are compatible with the halogen ones where as some require drivers. I believe most now have circuitry in the lamp to allow them to use normal halogen ones but always read the lamp spec before taking a chance