One of the ways I estermate price is look to see how much similar things go for on eBay, i.e. the price at the end of the auction. Failing that take the "new price" and half it, may be only chop a third off if it is really new and in good condition, still have all the boxes, cases manuals etc (don't forget to look at shipping costs !)!

As for Fender Strats ( I have 3), you should be ale to pick up a really nice one second hand for about 5-600 USD