its probably not burning oil, its most likely sludged. especially if the oil light is on. that light is set by low oil pressure, like what happens when the pickup is clogged.
pull the valve cover off, i guarentee you it looks like someone took a shit in there. if it isnt smoking, it isnt burning, that oil is just building up inside your engine.

it can be fixed, and cleaned out, but its a time consuming process, and somewhat expensive. valve cover, valve guide seals, and oil pickup need to be replaced, and the engine completely cleaned out.

there is a service campaign through toyota dealers for the sludge, and could possibly be covered under warranty, but youll have to prove the oil was changed every 5k miles. and if someone dumped the car that cheap, i doubt it was.