Since your just starting out, it would make your life easier to buy it directly here. Like zenox said you just can't have multiple users but you can use it on multiple machines. For spprites any art program will do, Photoshop, Corel Painter, or any of the free ones like paint.net.
For sound effects there are some that are included when you purchase, but there are lots of sites that offer stock sounds, which can be editted with Auducity which is also free. Hope this helps. Cheers