I know how much incontinence supplies add up! They are so expensive. When I was caring for my parents I got the Poise Pads and Depends at Costco - that was the best price then - but that ended 4 yrs ago - but it's worth checking there and Sam's Club, BJ's etc. - sometimes the cost of membership is worth it to get the discounted supplies.
I'm not aware of AARP having any discounts on incontinence supplies.
There are some medical supplies companies that will ship supplies - I have not tried them personally but I know some people have used them. If you do an online search for "home medical supplies" or "incontinence supplies delivered to home" or "discounted incontinence supplies" you might come up with some alternatives.
Hope this helps! Let us know if you do come across an alternative that saves money!
Take care,
Amy Goyer, AARP Family Caregiving Expert