I've found some size 2 undies at the Loblaw's chain of grocery stores here in Canada, that's whatever store carries the "President's Choice" brand in your area (different store names in different areas).
I've also gone ahead and bought those expensive undies for diaper-free babies. We did diaper-free and she was in underwear occasionally from around 10mo, I think, and exclusively in undies during the day from... I don't remember for sure, a little over a year old?
I bought a whoooole bunch from continuum-family.com. They were like $8 each. I did join her referral program so I was able to get quite a few for free, once I'd built up some credit. Also I was fortunate to be in on the game when she was just creating her tiny undies, and DD was one of the testers... so we got a couple tester pairs for free or for dirt cheap.
I don't regret the expense. Now that she's 3 and we've bought several store-bought undies, I can really see the difference. I'd get more of these expensive ones if she made them in bigger sizes!
Store-bought panties ride up like crazy, she gets constant wedgies. The handmade ones fit perfectly. Storebought are made with flimsy, thin fabric, the handmade ones are thick luxurious jersey (and are available in several different fabrics, including organic cotton, bamboo, wool...). The handmade ones also just plain fit better... the storebought ones are often too tight around the legs, or too loose, or snug around the waist while bagging around the butt...
It might be different for boys' briefs, in terms of fit, I don't know.
In our case it wasn't a crazy investment either, once you figure for how long they last. We started wearing them before she was a year old, and now that she's 3, she's just finally now outgrowing them. They fit her well for a good 2 years! And they're still in GREAT shape... some of the storebought ones we bought less than a year ago are already stretching out the elastics or wearing through. Our handmade ones are still like-new enough that we could easily pass them on to another child, if we have more.
