Favorite source for shirts?

[Dollander]

First off, if you want something washable, I'd recommend going a step up from the Spork Kilt to a USA Kilts' Casual model. I have one of the former, and I pretty much reserve it for the gym...or to throw on when there's an unexpected knock at the door as one might with shorts or a bathrobe. I'd consider it well worth the extra $40 for the USAK Casual, as it's much more suited to be worn as regular clothing. While I don't own one, I have seen them in person, and I've made myself several kilts from the exact same fabric.

For casual dress, any shirt you can wear with trousers can be worn with a kilt, provided the pattern doesn't clash. I may not be the greatest example, but for normal, day-to-day wear, I just go with darker-colored pocket t-shirts and plain sweaters, depending on the temperature. So if that's a little too casual for your tastes, those Goodwill finds you mention would be perfectly fine. There's nothing wrong with those grandfather shirts if that's what you like, but don't feel like you need to have a "kilt shirt" just because you're wearing a kilt.