There are plenty on Amazon.com
I have not bought one yet but I want to. I've done quite a bit of exploring around on Amazon.com reading reviews, it is a good resource for that. Once you find one that fits your needs, then you can try googling the model number to try to find it somewhere cheaper. Amazon is usually a good deal, though. There are most likely some on Ebay, too, but I'd definately read the reviews on Amazon first.
I have SAD and I recently moved from a very sunny, warm climate to a dreary, rainy one. That was tough to deal with at first but I find just regular (bright white) florescents (or CFLs) to improve my mood a bit. I recently put nice bright white CFLs throughout my whole house and its much nicer in there. Also, if you think you might have SAD, start taking vitamin D supplements every day. It did wonders for my mood.
I definately want to get a SAD lamp with a wakeup feature for the winter when its dark outside in the morning. I hate getting up when it's dark. The lamps with the wakeup features start getting gradually brighter over the course of a half an hour before you need to get up so its like the sun coming up. I think that would really help me to perk up in the morning in the winter.
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Non-NT something. Married to a diagnosed aspie.
Nothing is absolute.