Used sets sell for between $175 and $250 depending on condition and whether the box and instructions are included. If i was in the market for a used one to flip, the price paid would need to to be no more than $130 and the instruction booklet included. Too many risks in a used one (e.g. Discolored light gray gray elements need replacing).
I woukd pay $300 for a sealed one. However, compounded growth has seemed to slow down. On the positive side, there's another SW movie due in 2015. So if you can hold the set until May 2015, you might see a 50% gain with some luck.
Others will tell you to invest the $300 into another set that has more growth potential. That also makes sense. I compare the 10175 to a safer / conservative stock investment : lower growth expectation with minimal risk. Same could be said about most older movie themed sets without a "true" refresh.
One advice. To maximize sale potential, be sure to list it globally.