Aldi is a great way to save a lot of money on food. They have mostly their own brands, so if you are brand loyal you may not like it as much, but I have found the quality on most items to be very good. They don't take coupons, even when they do have some name brand stuff. I almost never buy brand name stuff there because i can do better on those elsewhere with a sale.
But for staples that you need and may not be on sale elsewhere they are great. For me they have the cheapest price on things like milk, eggs, hamburger buns, flour tortillas, and such. Their meat prices are competitive with sale prices elsewhere, and their produce is usually pretty cheap too. I have heard that the quality of the produce varies a bit by loction though.
When they open a new store they usually have store coupons in the paper or in the mail for $5 off a $30 purchase so keep an eye out for those.