Note: This deal will only work for anyone who has already pre-ordered the Spider-Man Playstation 4 Pro bundle from Gamestop, due to them closing down any new pre-orders. It also will work if you don't mind waiting a while for Gamestop to get more PS4 Pros back in stock (who knows when that will be).
Dollar General is having a sale on gift cards through 8/11, including Gamestop. Buy a $30 gift card and pay only $25. So, $390 in gift cards will cost only $325, bringing the total pre-tax total of the PS4 Pro SpiderMan bundle to $334.99. You could also purchase an additional gift card to save $5 on the tax. You can then use the 13-14 gift cards to pay for your purchase when you go to pick up your PS4, since you aren't charged when you initially make the pre-order.
Unfortunately, Gamestop stopped accepting pre-orders in the past day or so, which is unfortunate because I just picked up $420 in gift cards yesterday and today. If anyone has an extra pre-order that they aren't going to use, I would be super appreciative if there was some way to transfer it to me
FYI - Dollar General DOES NOT have a policy that limits the number of gift cards that you can purchase. I confirmed this explicitly with their corporate office. You can only buy these gift cards paying with cash, however.