As far as I know, grocery stores in Merida don't mail out their sales flyers, you pick them up at the front of the store.
My timing, when I have gone grocery shopping in the past, has not coincided with many great sales.
But, this time, I found several items I wanted and several were on sale:
I had been looking for some dessert bowls for several weeks. They usually ran about 20+ pesos a piece. I found some glass bowls in a store like "Tuesday Morning" for about 7 pesos a piece. They have an simple apple design around the rim. Pretty good find.
Been looking for vegetarian bacon bits to add some flavor to some recipes, found some and they were on sale. Bought two jars because in Mexico if there's a product you like, you need to stock up because it may not be there, again.
Also, found large cans of Salmon, got two. I had been looking for them to be restocked for months.
Found some canned mandarin oranges, a favorite. They were on sale, got two.
Been thinking about "How to Eat Ethically", I love tuna fish but know that often they are overfished and other animals die in the process, so I was happy to find a brand of tuna fish labelled "Amigo del Delfin." Let's hope they are. The price is about the same as other brands.
Getting olives in various containers was an experiment to see which size was the best price for the amount of olives. Bag of olives: 12.50pesos (1.70g), deli olives: 26.20 ( I think the deli olives won.) But, now I have a lot of olives.
Some brands of pasta do sell "Integral" pasta, a grain pasta, but I've never given them a try, so I got two, no price difference.
Also, I found a bag of popcorn seeds. I wanted to avoid the pre-packaged, flavored kind.
Don't usually see cereal on sale. Got a box for 29.90pesos, usually about 45.99. Cereal and peanut butter remind me of my brother-in-law. He likes cereal any time of the day and eats peanut butter from the jar as a snack. Sounds good to me.