Why cant I find season 1 on dvd?!?!

My boyfriend loves the show and I want to buy him the series for his birthday but season one is nearly impossible to find, at least for a reasonable price! Only a handful of places have it in stock and they sell that season alone for close to $100 and frankly as much as we both like the show 9 episodes is not nearly worth that much. A few months ago you could find it nearly anywhere for about $39 now nothing.....

Anyway if anyone knows where I can find it or is selling it(for a reasonable price) or in the very least can tell me why it seems to have been taken off the market it would be very much appreciated!