I'd recommend either of the ALPS Mountaineering lightweight one man tents -- the Mystique or the Zephyr. Both are less than 4 lbs and are readily available for less than $100. Amazon has them for $76 and $90, respectively, with free shipping. You can often find them cheaper on places like Sierra Trading Post.
They aren't ultralight, but from everything I've read, and from my experience with ALPS products, either one should be solid and last a long time -- a notch or two up in quality from the Texsport/Wentzel/Coleman single man tents that you can find in the $30 range.
The Eureka Spitfire (I think someone else may have mentioned) is also a solid choice, and a little lighter, at ~3lbs, and a similar cost of $90.
Of course, my ultimate recommendation would be to watch for a great sale, something on geartrade, or something on these forums. I know you were looking for other options, but in my experience, those are still the best places to go for a great deal.