Target stores have Starbucks coffee shops . They will give you grounds straight from the machines - filters and all . Not all employees know about this but I have never been refused . Also Barnes & Nobles have Starbucks . Try Dunkin Doughnuts shops too. The more of us who ask , the more the store employees will become accustomed to the question .
None of these places bag up the grounds and have them out like real Starbucks stores do , but they will still give you grounds if you ask .

Let's all remember that Starbucks is not the only place which produces this gardener's gold. I get all of mine from a convenience store located at a gas station which sells tons of coffee. It's also on the way home so no extra gas money to get the goodies.

A friend who I introduced to composting is now constantly beating me to the local Tim Horton's. I've decided not to tell her about the fish monger.

I have been collecting Starbucks grounds for about four years. One thing collectors might not know is that Starbucks throws away most of their grounds. I estimate the nearest store pitches about 70-90% of the total coffee grounds.

For the first six months, I went inside the store and requested grounds. I received one bag which was welcome. One time they had none, and I asked permission to check the dumpster. With permission, I checked and found four bags.
After that, I never went inside and always checked the dumpster. My average haul is three bags, once I learned what day trash collection was.

Inside the store the collector is given only espresso grounds. In the dumpster you find both espresso and regular grounds. While the regular bags include trash (which the espresso bags do not), the grounds have more moisture and are not in clumps like the espresso grounds.

I use a special rake to hook the bags and transfer the bags into my Rubbermaid container. One has to grab the bag by the knot. If you hook the bag it breaks. If there is a mess, I clean it up with a brush and pan. The trash is sorted once I get home; and goes in my weekly trash collection.

What are the benefits of coffee grounds? Do they benefit potted plants?

Coffee grounds are about 2% N, but they also provide other nutrients. They are also a source of organic matter. I'm not sure I'd want to use them for potted plants, though. They often sprout some funky looking molds that are fairly innocuous in the garden, but not what I'd like to see in a house plant.

Thank you.