1999 Toyota Corolla car bettery life

I thought because I got my batterys from walmart that I was getting bad ones so I weent to a different auto store put the new battery in and it worked fine it always does until I let it sit for a week or more without going anywhere everytime the battery is dead it will jump but after a couple hrs its dead again and I get a new battery cuz theres no charge left in the old one and the procecss goes on this newest one I get 3 weeks ago I have let my car sit since 12/18 and today the 29th I finally go to use it and its dead again