For BingCashback, you'll need to create an account or just tie it to a hotmail address.
Bing Shopping
Once you've created an account, use IE (seeing as it's a MS based program) and go to bing.com. Search "Wirefly" and click the link in the banner at the top indicating "$50 Bing Cashback".
It will forward you to the site, where you will place your order, and should later receive a notice for $50 via Bing Cashback via whichever email address you added to your Bing Cashback account.