Another option is to rent. REI & Sport Chalet rent gear. Although I'm not 100% sure about sleeping pads. Might be worth checking.
Last year Sport Chalet had a deal if you rented any camping/BP gear and then decided to buy the gear, the rental fee would be applied to the purchase.
And I'm in agreement with Bee, sleeping gear should not be an area to skimp. I'm a slide sleeper and use a Big Agnes insulated air mattress and blue closed cell foam pad.
Another good site to check is Steep & Cheep.
