First find the number of Best Buy gift cards Jack needs to return: 6 cards - 1 cards = <<6-1=5>>5 cards
Then multiply that number by the cost per card to find the total refund Jack gets from Best Buy: 5 cards * $500/card = $<<5*500=2500>>2500
Then find the number of Walmart gift cards Jack needs to return: 9 cards - 2 cards = <<9-2=7>>7 cards
Then multiply that number by the cost per card to find the total refund Jack gets from Walmart: 7 cards * $200/card = $<<7*200=1400>>1400
Then add the two refunds to find his total refund amount: $2500 + $1400 = $<<2500+1400=3900>>3900
#### 3900