I'm quite the connoisseur of cartoon underwear, and have come across some really good deals, and felt that ADISC would really appreciate this.
On Ebay people are selling some nice childish boys briefs that are size 14-16 and 16-18. I particular there are these cartoon Christmas underwear being sold for cheap that I love an adore and have bought. So I recommend that if your looking for cheap nice looking kids underwear check out ebay, and the cartoon christmas print 14-16 ones are a perfect fit on my 30inch waist. I would say they could fit up to 32-34inchs.
Here is a messy link to the boys underwear section.
boys underwear | eBay