Most guarantee the sale for 30-45 days. I typically use it within that time, and some of the cards have huge discounts, others I save a lot on because I shop a lot there over the course of the year.
Michael's, Petsmart are 18% - 25% discounts. The michael's cards combined with their 40 or 50 percent off coupon keeps the kids and I in crafts, school supplies and toys for the year.
I'll get
Walmart at 3.5 percent or target at 6% because I spend so much in their stores over the course of the year. I used to not bother because their percentage is so low but Walmart is our main grocery store for our family of 5 and where I buy the kid's basics like underwear and socks, and household goods, gardening supplies even alot of home improvement stuff like sandpaper,paint rollers etc (and our house ALWAYS needs work).. Averaging in the holidays they probably end up with $500 or more of our money a month. That's over $200 in pretty low effort savings a year. Lowes and home depot can be found for 8%. Airlines like Southwest 8%
We try to stay out of restaurants but when we do go to a chain we always have a gift card. Saving $5-$10 when we do eat out adds up, another $100-$200 a year, more if you count vacations. We only get cards for things we are doing anyway, so it doesn't become an excuse. Also, having to plan ahead for purchases by a couple of days is a good strategy to see if something really is worth it. All told the amount we save just doing the gift cards pays for a modest trip for us to Disney. For us it is like a rewards credit card without the risk of interest if something goes wrong and a slightly higher return. So it is worth it to me! Mortage, Utilities, and Gas and the doctor are just about the only things we don't pay for with these. I even paid for my kid's horseback riding lessons with tractor supply gift cards last week at the instructors request. She ended up with a little more then she would have gotten and I ended up paying a little less.