You can get a Wii online for a good price at eBay. Sometimes at Amazon. You should compare prices online. Check classiefied adds and penny auctions, too.
You Will need A sensor bar to play wii You Get it when you buy a wii but if it gets ruined you can get one for a good price on www.ebay.com
get a PC because it have a good games for lower price
They can range from $5 to $14.99 depending on what retailer you are going through.
about $249.99
costco has a good standard price, any better than that will have to be a sale.
The closest you will get to retail at the moment is to check out this guys advice on where to buy a wii in stock for Nintendo Wii price and not the post xmas price. http://wheretobuyawii.tumblr.com/
No you can trade in a Nintendo Wii towards the purchase price at a Gamestop or similar store, but you may get less than half of there selling price for the Wii.
$279.99
A Nintendo Wii system costs approximately $250. The price varies from store to store so it is a good idea to check the prices before making a purchase.
GameStop
It all depends on the price of the xbox 360 and the price of the wii. I am pretty sure that they will let you though.