You may want to try
bricklink.com. This is an "Unofficial LEGO Marketplace" where users can buy/sell anything LEGO related that they want to. Be warned sometimes the searching can be a bit difficult because there is simply so many items listed, but once you get the hang of it it does make sense. I did a quick search and it looks like you can probably get one for less than $300, give or take depending on shipping costs and New/Used. I've used this site often so please let me know if you have any questions about it.
I hope this helps
-Calvin