Maybe that's why they're so cheap because the sizing varies so much? But for $12 you can't go too wrong. The link I just found when I was looking for a picture of the shirts.
Luckily I was able to fit try mine on at TG Maxx. But I normally wear a medium t-shirt and this fit like a mountain bike jersey(which I like). Maybe after a wash it'll shrink a little for folks and wanted something smaller. Maybe dry on low/extra low?