So, you just bought a bag of coffee, you open it, and then what? Once opened, coffee beans, and especially ground coffee, have a pretty quick shelf life of 5-7 days, depending on how it is stored. Plastic airtight bags are an alright choice, but don't expect too much from them, kind of like that box of tapioca pudding that was in your cabinet that expired 6 years ago.
When trying to find something to store your coffee beans, look for airtight containers, preferably ones that don't allow light to come in. If storing coffee in a clear container, keep it somewhere dark where the Sun won't bother it too much, as the UV rays can make the coffee lose its freshness faster.
There are a plethora of products on the market that are designed for coffee storage. I have a Coffeevac branded one that works pretty good, as it is 100% airtight, and holds an entire pound of coffee beans. The only downside to this product I have found, is that because it is made out of plastic, it can be difficult to remove the scent of whichever beans I had in it prior. If you find that this is an issue, there are several similar products made out of glass or ceramic.
Some products will include a vacuum type deal that draws air out of the container portion, but these are also best left on the store shelf. This is because the vacuum will actually pull oils and air out of the actual coffee beans, thus giving them a strange flavor. Vacuum sealing is really only good for pre-ground coffee, and even then, it still has effects on the flavor. When looking at coffee bags, always look for the little one way valve that is usually located on the front. This valve allows all the carbon dioxide to escape during the degassing process of the beans, and prevents any oxygen from reentering the bag afterwords; guaranteeing fresh coffee.
Always avoid storing coffee in a refrigerator. While it might seem like a good idea, because the place is dark and cool, it will actually age your coffee much faster. You know when you have fish in your fridge for a couple days, and then suddenly tons of stuff tastes like the fish? The same thing can happen to coffee. Since coffee is relatively porous, it can absorb lingering scents and flavors inside of the fridge, even if stored in something airtight. There is also a lot of moisture inside of a refrigerator, and if the container of coffee is opened taken out and opened a lot, water can actually build up inside of the container, ruining the coffee.
The freezer is an iffy one. Coffee should only be stored in the freezer if in an airtight container or bag, it will never be put back into the freezer, and the coffee will be stored there for more than a month. The freezer is an okay place to store a large amount of coffee for a long time, but if doing this, always make sure to let the coffee sit, still perfectly sealed, outside of the freezer for a few hours so it can adjust to the temperature. If opened before it is at room temperature, moisture will flood the container, and make your coffee beans pretty sad.