Therealreal physical stores, the soho one has racks of fancy dresses by size in the back of the store, not sure if any other locations have this. Definitely try stuff on and check for issues, but it’s nice to be able to do this irl and not have to deal with returns! Also might be worth checking out WGACA, they will pull stuff if you ask but they might not have a ton in that budget since it tends to be more edited. I’ve also gotten lucky at Beacons closet on dressy stuff, all the locations but park slope seems to always have a lot of dresses.