I have 2 from Target. One is an underwire and it's really comfortable. It's just white cotton- wish they had it in black too, but they just have white and nude. It was $14.99.
The other one is
AWFUL. Avoid this one! It's not underwire, just has a sports-bra type elastic band. Apparently it's a sleep bra, which is why the material is so comfy, but I didn't realize and wore it as a regular bra? Maybe that's why. By the end of the first day wearing it, that band had folded in half. There's a crease now that doesn't go away- not great for support! Also the inner lining is mesh, which is nice and breathable, but it is oddly higher than the bra, so it can be seen with v-neck shirts.
My favorite bra right now is actually just a sports bra. I just lift it up and get the boob out from the bottom. It's so much easier than fiddling with the nursing clasps.