You missed getting these sets for about $17 or so shipped total from Circuit City back when they were still in business. I got them for that price back on Black Friday.
They had the individual sets for S1 and S2, as well as a 2 pack with both seasons listed for under $15 total, I believe. I picked up the two pack, which took 2-3 weeks to come back in stock, but I managed to order when it was backordered and it STILL shipped.
Now, if you have S1 & S2 of Robot Chicken or S1 & S2 of Transformers Generation 1, I'd do an even swap for those season sets.
You also might want to check WalMart, since I think I've seen the two pack for $30 something there. They used to have it listed on their site, but I didn't favorite place the link.
EDIT: I found a compilation of Seasons 1 through 3 available from Family Video for $61.99:
LINK
However, I know that was more than you wanted to spend, but you DO get season 3 with the set, which JUST released.
By the way, I read somewhere they're capping the series at FOUR seasons, with this one being their last.
EDIT(AGAIN): Walmart.com has site to store shipping(FREE) and the two season set is $43.86 there. Sure, it's over the $40 total you wanna spend, but not by much:
Link