"Value" is a quality that means the amount of use or enjoyment that you get from something.
"Value" is similar to "price" in some ways. But the "price" of something means how much it actually costs, while the "value" means something closer to the "real" worth.
When something is "a good value", it means that its value is high compared to how much it costs. You use it like this:
They aren't cheap, but they're a good value.