Yeah definitely keep the coffee in whole bean until right before brewing. There are good burr grinders out there for as low as $70, so I can't see why everybody serious about coffee thinks they can get away with preground.
What I do for my beans is keep them in the original packaging and put the bag in an airtight container, then suck the air from them with a FoodSaver device. This works quite well. Later!
A cheap alternative is the Reynolds vaccum device that uses the zip-loc type bags. Not as effective as a Food Saver, but for about $10 it works quite well. We use the Food Saver for all sorts of things and the bean storage is just one of the many uses you'll find for it. Later!
Reason I ask is b/c I get my coffee grounded up at the coffee shop. Really can't afford a coffee grinder right now, being a grad student doesn't pay much, hahaha. So yeah, I just wanted to know if it was pointless to store grinded coffee in air tight containers.
When I know I'm going to be very busy, I sometimes ask to have my coffee beans ground rather than grind them myself.
I usually only get 1/2 pound ground at a time. When I get then home, I immediately measure out what I'll need each time (for example, 6 tablespoons of ground coffee for a small 36 ounce pot) and I put the coffee into fold-top sandwich bags and squeeze the air out and close them with a twist-tie (I grab a few extra twist-ties when I go to the supermarket)
Then I put the pre-measured bags into a freezer bag and freeze them. That way, I only take out what I need and the rest stays frozen. This seems to work okay, and the coffee doesn't go stale and bitter as fast as it would if I had left it unfrozen.
I have also tried putting a few of the pre-measured bags into one of those canisters (posted below) and the coffee seems to stay okay for about a week. Since you use an Aeropress, you may just want to keep out only as much coffee that you'll be using for a day or so and freeze the rest.
Although it's not generally recommended, when I buy whole roasted beans, I do the same thing, but I usually put the pre-measured bags into a container (similar to the one posted below) and only take out what I need.
If I buy a couple of pounds of beans, (if I find a good sale) I pre-measure what I'll need and freeze them in a freezer bag that I put inside a Tupperware container. They seem to be fine when I use them.
I wouldn't get the beans ground and put the whole lot into the container. The coffee will be exposed to too much air each time you open the container, and soon the coffee will smell like glue and taste terrible.
I guess you'll need to experiment and figure out what's best for you.