Need help fast

The base total is how much you are paying. So you would pay 991.38-$6.52(base - tax). You get the rebates after you purchase the items, but it could take a while to get the rebates (2-8 weeks usually).
 
On PCPartPicker, the Base total is the total of the parts BEFORE shipping, Mail in rebates, and Promos.

Here you have a promo discount of 6.52 and 115 of mail in rebates. According to PC part picker, you will be paying about $985.

If youre thinkning about not doing those mail in rebates, you should do them. They are really easy,