10 dollars won't probably get you a good wireless adapter. I would recommend getting a wire to connect from the router/modem to the computer. If you can't do that well... get this-
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
It is the closest to 10 dollars, and should serve you... OK. It is a little bit slow, and when it goes under load (As in downloading things) SOMETIMES it will drop signal. But it won't drop signal randomly other than that.