I’m very small. Where can I find affordable dresses and skirts?

wear a size 00 (sometimes 0) in juniors and a size 12 (sometimes 14) in girls. I need a few nice dresses and knee-length skirts. The skirts should have some sort of print or color in them and be A-line or a similar shape. The dresses should not be low-cut in the neckline. Pictures, links, and stores would be helpful. I’m a teenager, so I’d like them to look a bit more mature or trendy than most things in the girls section. And please don’t suggest Abercrombie & Fitch, Aeropostale, Hollister, PacSun, or American Eagle as they do not have anything I’m looking for. Specific links please! Thanks!
Oh yeah, and I’m very flat-chested. The dresses need to be able to accomodate that. thanks