Why is HSN charging almost $500 more for the surface pro then Microsoft charges for the same system?

Part of the issue is overhead.  HSN is running a shopping channel with studios, broadcast fees, etc.  Microsoft does not.

Another issue, and probably a bigger issue, is Easy Pay.  Easy Pay costs money.  HSN is essentially financing the purchase over several monhs, and there are always people who end up skipping out on their payments or not having enough to pay it off.  These costs have to be absorbed by HSN, and as a result, item prices may be higher.

Ultimately, though, HSN is entitled to charge whatever it wans for producs without explanation.  You have the option to purchase the product from another source, so why HSN does something really should not be anyone’s concern.