Here are a few button-up shirts that I found I don't wear, but are wonderful (side note: I only just found out the "button-down" refers to those little buttons at the collar points, not the row of buttons down the front of the shirt. Learn something new every day, I guess!)
First: this Tomboy Style x Tradlands green and white stripe oxford popover is seriously great. Everything everyone's said about Tradlands is true: the quality, workmanship, and design is excellent. I have this in purple stripe, though, and I really only need one. I'm pretty sure this is still on the website for $165, and I wore this 1x last summer, so you'd be getting a really sweet basically new shirt for quite a bit cheaper than list.
Size XS, but fits quite roomily on me, so I'd say this could fit up to a 6-8 pretty comfortably. Asking $100 + shipping. https://tradlands.com/products/the-busby is the purple version.
Next, this is a classic Lauren Moffatt pintuck shirt (man, I miss that company...her new one isn't the same). This shirt has her signature asymmetrical line of snap buttons, sweet pintucks in the back, and a longer front hem than back. The fabric is a thick woven cotton with blue and pink dots on it. Size M, pretty true to size. Asking $40 + shipping.
Finally, I have 2 more Gitman Sisters shirts. The first is a white oxford--tailored, clean, and really well-made. There's a faint makeup smear on the collar (see photo). Size S. Asking $35 + shipping.
The second is a blue cotton with little white woven-in dots, also size S. Sorry it looks so wrinkly! Asking $30 + shipping.
alb2199 at columbia dot edu for questions, and I'll combine shipping with anything else you might want!