The cheapest you'll get them is $21 ($3.50/diaper), vs. a pack of 22 (about $1/diaper), or a case of 88 ($0.75/diaper)from XP Medical. You can always add your own prints.
Very pricey, and I would never buy anything off Ebay from someone with that low a score.
Couple tips on Ebay:
1. Always calculate shipping in the final cost. Sellers will raise shipping costs to make more $ without incurring more seller fees.
2. Don't fall for 70% of the "adult baby" garbage that people are selling there. Many are selling "baby diaper like" briefs that are el-cheapo institutional diapers (like Kendall Simplicity... $35 for a case of 96) with an easy to make cartoon strip taped to the front, for insane prices. Gotta be careful on AB clothes, too... Some onesies are poorly modified t-shirts, some are selling clothes that they only make after you buy them (and take forever to ship), and so on.
3. Pay attention to feedback, and not just the percentage. If a seller has negative feedback, check the feedback of the person that gave it to them... If they have a good rating, it's probably a safe bet that the buyer had a genuine gripe. My personal rule is 98% or better, and at least 50 feedback. I haven't been burned yet, and buy (and sell) tons of crap on Ebay.