I highly recommend getting a Sam's Club membership if you have the means. We've had ours for a little over 2 months, and we've already saved $154 on things we buy elsewhere on a weekly basis. Well worth the $45 year long membership (plus they gave us a $20 gift card and $17 in food at signup).
And btw, those are based on Walmart prices, so if you're shopping at meijer or kroger (which typically costs $1 more than Walmart for the same items), then you'd be saving even more.