Is it healthy and safe to use outdated or expired food?

Yes...

The meats are frozen before they go out. The most that's out of date are can goods or boxed items and they usually are not that far out of date. The prices far out weigh the bad. I got a case of blueberries and there wasn't even 15 berries that were bad. If I would have known that I would have gotten 2 or more cases.

For the most part, yes. Just use discretion. Canned and dry goods are pretty much fine well past their Sell By date. Meats are usually fine as long as they're frozen and stay that way. Non-frozen dairy, much less so. But as others have said, a decent amount of stuff there isn't out of date.

It is not all past date