Get something that's fresh, meaning it was roasted 3-5 days ago. Flavor quality begins to drop off after about a week after roasting and personally I wouldn't want something older than 2 weeks.
There's also no reason to pay exorbitant prices, usually good fresh coffee will cost around $8-14/lb. and I'm talking about very high quality beans, much better than anything in the grocery store or brewed at any cafe.