A SAD Light you wear! The ultimate in portability. This means you can get your light therapy on the move.
The Verilux Happylight Personal is very inexpensive indeed and it comes from a reputable brand name. It provides 5,000 lux and is small and well made.
The Northern Light Technology Travelite puts out a lovely warm light, but it is quite pricey. What else do you get for your money?