It's totally worth it if you time it right. I bought my membership ($20) when they released their 20% off coupon. At the time I was buying a backpack that was over $100. With the coupon, the membership paid for itself. Now im just collecting dividends for the rest of my life. Whether they are small or large dividends, its still a rebate on stuff I would buy anyways (mainly fuel, small things like water bottles, repair hardwear etc).
Because you live far away, I take it that you can't utilize their "free ship to store" service, and you're less likely to swing by there to grab consumables...so maybe not so much for you