I shop at a wide variety of grocery stores, around the country. Most grocery store chains offer better prices if you check out using a 'membership card' of some sort. Unfortunately, most chains are pretty regional, and I'm really not interested in signing up with all 20 of the grocery stores I shop at in any given year... to say nothing of the privacy implications of allowing the grocery chains to track my every purchase.
How can I get access to these better prices without signing up for a card myself?
At most of our local stores, the cashiers keep a card at the checkout counter. I think it may be mostly for people who forget their own card, but I've found that if I'm honest & just say I'd like the same discounts without having to register, they run that card through.
Most checkout systems will allow you to enter a phone number, in lieu of presenting an actual physical card. While you can guess at a number by using famous numbers like 867-5309 or 555-5555 with a local area code, I find a much more reliable method is to use my smartphone to look up the phone number of the store at which I'm shopping.
Since most stores have a 'store card' tied to the stores phone number, you can just enter this number at checkout, and it will often work just fine.
I visit Las Vegas once a year and sure enough never remember to prior year's card. So I just go up to the service desk and ask for a new card and say "I'll fill in the form later and bring the form back next time as I'm in a rush now".
Always been given a card and it always works. Never returned a form and even the prior year's cards work when I remember to take them. You probably don't get all discounts but the ones on the shelf for carrying a card always work.
There are many ways, though in some cases it depends on the store policy and/or their staff.
You can just ask for a card, without saying anything about agreeing to fill out the form. I have done this many times, and unless it's a credit card, Radio Shack, an actual membership with a fee like Costco, or a department store or something, I have never (at supermarkets or the non-drug parts of drug stores) seen staff want me to fill out the form before using it. It would just slow them down to wait for you to fill it out, and even when there is no one behind me in line, staff have given me cards and even encouraged me not to fill out the form.
You can say you don't have a card, and many staff will use their own card, or the register's card.
You can ask your friends and family if they have such a card, and whether they mind if you use their number for it (usually the phone number). The cards usually come in family packs anyway with four or more cards for each form, so they might even have a spare card to share with you.
You can also trade/share cards with your friends, or strangers, or use cards you find lying around. I wouldn't recommend giving away cards to untrusted people IF they have your actual information, however, as both stores and law enforcement may try to use shopping history as evidence in lawsuits and criminal charges. (All the more reason to not give out your information, though.)
At a number of stores I've gotten them from, if you simply say that you are in a hurry and will fill out the application later, they will scan it and let you go on your merry way. Then, just load that into an app on your phone (I use KeyRing too) and forget the physical card. That is how the cards are that many stores use at the registers. They often times are not registered and we just ones grabbed from the stack and used. At least at the few I worked at that is how it was done. It was also advised to have them scanned if the customer did not have one right away - the point was to make sure the customer got through the line as fast as possible to speed up checkout times. Some places like Kroger, track the times of cashiers, so they will scan the store card to help speed things up.