Have you used diapers.com?

Has anybody used diapers.com before? Is it a decent place to get diapers? They are telling me that with a discount code I can get 276 size one diapers for under 40 bucks..... Do you have to pay for a membership or anything. I noticed tho that diapers and wipes are pretty much the only things that are cheaper, everything else costs more or about the same. I would just like everyone's feedback on it! Thanks!