Yan 

They are not hosing you. Yes, shops are more expensive than Ebay, but you pay for the expertise and the convenience of having someone always available in your neighbourhood to assist you. Your wheel may well be salvageable by a skilled wheel builder. You haven't posted any pictures so none of us here can give feedback. If you buy a wheel on Ebay, you'll never know. In two months when your questionable quality eBay wheel goes out of true, rather than being able to take the wheel back to the shop, you will have to buy another wheel on Ebay. If you really are interested in doing the work yourself, properly, then I recommend the Park Tool and Sheldon Brown websites as good starting points for wheel building. It is not a terribly difficult process, but it is quite involved and takes some patience. Good luck.