These discounts are clearly made to get everyone to hand over their numbers so the chains can build a profile on each customer and serve them better ads. It’s still a concern that they can learn so much from your shopping habits.
I’m sure these discounts add up over time, is there a happy medium?
I live in Los Angeles and I get member discount offers at Vons, Ralphs, WholeFoods, and Rite Aid. Since most phone numbers can easily be connected to a person, I decided to give all of these stores a fake number that I can always remember. This number can’t be connected to me and I continue to get the “member discounts”, but is there any privacy downside to them having my “buyer profile” even with a random phone number?
I usually decline but sometimes I just use Pizza Hut’s phone number.
Local area code + 867-5309. Jenny has given me many a discount. Harder now that they often only use verified numbers. 
Do you they have your name? Do you use a debit card in your name? Does the store have cameras? They can always tie the account to your identity and then they track your purchases, times and locations every time you do it. I avoid ‘rewards’ programs. Everyone and their mom has a rewards program now so they can collect as much info as possible.
Some places like Kroger stores will ask for a 10 digit number ID, with formatting angled to imply a phone number, but not actually require a phone number. I made up my own number for Kroger, and I think OP understands and has done the same. So I suppose I only mention that to remind comment readers that it might seem necessary but doesn’t mean one is required. Might as well give using a fake number a shot first.
7/11 doesn’t require a working phone number. I just punched random digits in.
I guess the one thing to consider when using a ‘loyalty card’ with a phone number at a grocery store is Food Safety Recalls. I belong to a large supermarket in the USA (Wegmans). Over the past 10 years or so, I have received 2 automated telephone calls from them informing me of food recalls, each resulting in me returning the item for a refund and preventing me from consuming the tainted food item.
No discount is worth having to provide personal information to get it. Just say no.
Use a fake number, or just don’t give them a number.
You don’t actually have to sign up on a lot of these programs. For example, Smith’s grocery stores keychain barcodes will work without ever actually enrolling in anything.
What I find amusing about those programs is that Wal Mart doesn’t have any of that shit and they still kick everyone’s ass on price. Everyone else wants my key tag, my member number, my phone number, my zip code, my email, like WTF? Can I just give you money and get my shit please?
They’re going to track us anyways. Whole Foods is littered with cameras now, Best Buy tracks the location of your phone by IMEI to see where you stop, probably everyone else too.
At least grocery stores and pharmacies give you something in return for all their tracking.
I give them my ex wife’s number. She has the account, any purchases go to her history, but I get discount.
I use mysudo that provides virtual numbers. I’ve got one dedicated for these kind of things.
Most of the time they’ll just give you the card if you’d prefer to carry the physical card. Or populate it with 10 meaningless (to you) digits. They’ll still build a profile, but it will be sandboxed
If you live in the town you grew up in you can use your childhood friend’s mamma’s number. This always works for me at winn dixie.
I give a burner number. I guard my actual number hard.
They can figure out the same information if you pay with a debit/credit card. The phone number just allows them to link data between cards because most people tend not to change phone numbers.
I use the number of a landline at work (vacant office).
I always decline, but exactly for the event of them insisting on it, I carry a sex shop number in my phone. Prepared
