The grocery store I shop at (only because it is nearest) has a savings card. When I walk through the store I see the items that will be discounted at the till when I pay. I usually see a savings of 5-15% on my bill (Which is printed in bold to let us know what we saved by using the card.) Earlier today I went in with a list of what I needed (I had a few items I kept forgetting to pick up so I deemed a list necessary). Several of the items were the type of things which I could select one brand over another. Several items were on sale if I used the card and I chose those products over the ones not on sale. I did well today - grabbed the items on my list, didn't make a lot of junky unnecessary purchases, but I did fall for the bait on one item. Lean ground beef was on sale which was not on my list. Of all the things to get baited on this was not a bad one, but it surprised me nonetheless and made me think am I really saving money with this card if I am making impulse buys? Today it was a 14% discount overall. If I recalculate my bill without the card or the beef and compare, however, I only saved 38 cents, far less than 1%. Are you really saving or being lured into spending more?
I don't trust the savings messages on the receipts, personally. Stores always inflate their "regular" prices to make it look like the items are steeply discounted at that moment. What matters more is how much you are saving at that store relative to what those items cost at other stores. You will often find the "sale" prices at one grocery store will often be the "regular" price for that same item at another grocery store - in which case your real savings on that item by having a card with them is basically zero. For example, there is a certain brand of soup base that I buy which normally sells for about $6 a jar at most grocery stores - but once in a while they will have them "marked down" to only $5. That same item is also sold at Wal-Mart for only $4 a jar, and that's their every day price, I don't even need to wait for any sort of sale.
I would get a discount card if the shop where I usually go has one. If you go there anyway, might as well have a discount card and save a little. What you shouldn't do is start going to a shop just because they have a discount card. The money for the discounts has to come from somewhere, and it's always the customers. So often (almost always) a store with a discount program will be more expensive than a similar one without the program. They also use it a lot in order to sell products which are getting close to their sell by date. This is mainly why I have a discount card, because sometimes I can get items for -50% and just stick them in the freezer. So yes, it's definitely is a two sided coin. Use them if you can, but don't start running after their discounts.
