first of all I have to say sorry for my englsih,its not the best, Im from Germany.
for my question:
sure,its much more easy to buy MREs in the internet/ebay or buy it in an army store which sales these US MREs (not so easy in Germany,no army store has the US MRE,just sometimes German army food called EPA

but I prefer to go out in training areas and look for MREs after a finished training/manouver of the US Army or if they moved from one place to another.They often throw away MREs and sometimes the MREs arent opened or just one or two items are missing/were eaten.
Its always great and funny to search for the MREs and Im much more happy to find MREs or items than to buy it in internet.
Searchin for MRE is like a hobbie !
Imon