I bought a set (6) of those LED lights some people use to light up the underside of their cars. Sorry, I dont know the official term for them.
Most auto supply stores carry them. About $14.
Over the years I've kept the power adapters that are used with telephones, cd players, radios, etc. Had one that was 12v.
You can also buy these power adapters at places like Walmart that have a range of voltages.