If it is a real MRE, it will last almost forever. In the 80s, my unit occasionally dined on food from the Korean War. Expiration dates are meaningless for that stuff.
But you need more than just one and you need to compare prices. I'm still not sure why this makes you stupid. I have MREs in my earthquake supplies. Everyone should have 2 weeks worth of food on hand that doesn't need to be cooked or refrigerated.
My father-in-law was career military and served in Korea and Viet Nam. He had MREs from both wars. The Korea MREs contained cigarettes and matches, LOL. I always liked to look inside the boxes to see what was provided - little can openers, etc. My father served in WWII and said that he traded the cigarettes for Hershey candy bars or other things he liked.