Stores seem to move their current ad page around on their websites a lot. So if any of these links don't work, just look around on the store's home page and you'll probably find a link for their ad.

food:

Giant Food

Harris Teeter

Healthway Natural Foods Coupons for items you select are emailed to you.

Magruders You can sign up to recieve ads by email.

My Organic Market Look for the current month's sales flyer link on the homepage. You can sign up for monthly ads by email.

Safeway

Whole Foods Market

stuff:

Best Buy You can check inventory on many items at specific stores online. Look for "check stores" for a given item you're interested in.