You can buy 5 cans of green beans at the village market for $3 you can buy 10 of the same cans of beans at sams club for $6.10 which is the better place to buy

Each can of green beans costs  ($3.00/5) = 60¢  at the
village market, and  ($6.10/10) = 61¢  at Sam's Club.

If you're watching every penny, then that MIGHT be enough
of a difference to make you decide to buy your beans at the
village market, but not necessarily.

If, say, the village market is farther away from you, or if there are
other things you're going to get from Sam's anyway, then you
should buy your beans there too.