I've talked about this before, but wanted to let you know about it again!
I just got my second set of diapers (for FREE!) from Arquest. They are a Mother Panel Research Group and specifically work with diaper companies. The process is simple. You sign up, they call when the size diapers you want are available. You agree to do the study and they send you the diapers (either 1,2 or 3 packs of diapers...20 in each pack!). You finish the diapers, fill out a quick survey and then they call (which is scheduled beforehand) for your answers. Once completed, they mail you a $10 Thank You Check!!!
The first time I did it I received Pampers diapers. After the experience I called to see how I could do it again and within a couple weeks, they called me again!!! This time around I got the Wal-Mart brand, but still it's 20 FREE diapers!!!
Here's the contact information. They may not have the size you need immediately, but leave a message anyway and they will call (when I called the first time Gage was in a 3, but I told them either a 3 or 4...that might help you get diapers a little faster!!!).
1-888-DIAPER2 Ext.646 (Georgia)
Ext. 634 (Cheyla)