Glad you started this thread, Face. I am probably in a different situation than you and most on here since we are retired. We have the $110 membership there and the $100 membership at Sam's. We buy probably 75% of what we need or want of regular stuff between both as we pick up things for other family members and a grandson. Sam's has stuff Costco doesn't and vice versa. The savings and rebates on Sam's and their Mastercard as well as the Costco membership and their related American Express more than doubles the annual membership cost of each.
Where the big money is saved is on big ticket items. At Costco we have hit it big on major purchases. We saved more than $500 on a 4 drawer Whirlpool fridge over competing stores that had theirs on sale and nearly equal prices to each other. They hauled the old one off and set up the new one using a contract delivery company. Today, I just completed the purchase of a new Buick Enclave, replacing a 7 year old version of the same. No hassle. Every month they run specials on manufacturers who are usually offering rebates of their own as well. You get referred direct to a local dealer. A salesman calls and begins the process with you. You select the vehicle and receive the pre-arranged Costco price, which is well below sticker. You negotiate any trade-in allowance. They apply any rebates. You buy the vehicle. The dealer gives you a form with Pin # to go online and fill out a redemption form. A Costco rep calls you to do a survey about Costco and the purchase. You then receive a $400-600 Costco debit card (depends on level of membership) to be used in their store - which you are going to spend anyway on regular stuff. It arrives within 8 weeks of the purchase. I used my Costco AmEx for the $3000 deposit on the vehicle - so I will get cash back on it as well. Since I bought from the same dealer, they gave me $2500 above book loyalty premium on the trade-in since they had serviced it all that time. Doing the deal through Costco saved me in the area of $4000+ over walking into the dealership and negotiating a deal - which is a royal pain in the posterior.