The only bait shop worth going to on Gvine is yates. They don't count their minnows like some and they are usually not busy. I would say call ahead though as they tend to sell out at times. The Valero station on texan trail is the worst. They short you minnows and they are sitting in those bags for hours when you buy them.
Agreed 100% on the Texan Trail Valero/Chevron, whoever they are; pre-bagged, huuge minnows, not worth the price or stopping to get them really.
Yates pretty much has Grapevine minnows on lock it sounds like, I was hoping someone chimed in on a spot I wasn't aware of either.
Not a lot of options, we usually just jig hand ties when we go out there for crappie.