You might look on Ebay. I did a search under LED table lamps and found several thousand listed for sale, many of which were quite inexpensive. I just looked at a few of them and saw some that showed the number of lumens. I would think you'd want a warm versus a bright white light for fly tying, but I'm not sure of that.

I recently bought a 4' long LED light bar, with a remote control on off switch with a dimmer from an Ebay seller, to backlight a stained glass window, and I couldn't be more pleased with it.