Sears offers the Craftsman 9-in-1 Drywall Folding Knife, model no. 96193, for $9.89. Choose in-store pickup to avoid the $5.99 shipping fee. That's $20 off list and the lowest price we could find. It features a quick blade change mechanism and several blade types.
Of note, Shop Your Way Rewards members will earn a Sears credit with this purchase and may be eligible for additional credits and discounts.