That's right twinkltoz, there is a lot of labor that people don't realize. It generally takes me about 8-15 hours to make a dress, depending on if I've sewn for the person before and depending on how complex it is. And that doesn't include the time to glue on all the rhinestones. Plus there's the time for fabric shopping and fittings. The fabrics that most "name" dress designers use cost $20-$30 per yard, and you need 6-10 yards or more per dress. And then there's rhinestones: even a starter dress would have at least 10 gross on it (more like 20 gross), which is another $7.50 per gross plus probably two hours of labor to stick them on (figure 5 gross per hour). Add in notions (thread, elastic, interfacing, drafting materials, hooks and eyes) and wear-and-tear on the sewing machine and the materials costs add up too.
People are very used to buying clothes made in third-world countries where the labor component of the price is extremely small. Of course a piece of clothing made somewhere that you only have to pay the workers $1/day is going to cost a lot less than if it's made in a place where you have to pay the workers $40/day minimum. Wedding dress seamstresses bill at $35/hour and more.
That said, I do think some people over-price their used dresses. My rule of thumb is that I take 10% off every time I wear the dress. I generally sell my dresses after I've worn them four or five times. Lonnie, who runs a ballroom consignment store, has said that you can't get emotionally attached to a dress when you go to price it for resale: it's just fabric in the end, so give it a price it will actually sell for. Personally, I would never spend much more than 50% of the new price for a used dress, unless it's a special circumstance where it was only worn once. And I don't mean once in a 5-round event, but for like one or two rounds and that was it.
I have several dreses for sale in your price range, but unfortunately they are sized 12-14 and so are way too big for you. It's quite difficult to alter a dress from a 12-14 down to about an 8, so I'm not even going to tempt you with my offerings.
