Over time, if you use them the right way, they can be.
I bought a vacuum sealer a couple months ago for the purpose of preserving meats. I plan on buying a large ribeye, for example, and slicing it into individual steaks and roasts. Buying in bulk like this saves money. I can seal and store the individual steaks in my freezer, extending their life by many months.
Vacuum storage is good for anything that spoils or oxidizes, to increase the life of that product.
So it depends on how you use it and how often. Mine cost about $50 or so. I have not yet recouped that initial investment, but I did buy some meat that I cut and packaged that saved me probably $20 over buying at full price, so I am on the way there.
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