Where local codes permit the Starbucks coffee shop to do so they remove the used coffee grounds from their coffee machines and then place them in the empty bags that the coffee originally came in.
Then you can go to Starbucks and request a free bag of used coffee grounds for your garden and they've been doing this program since the year 1995 which has been 24 years.
The coffee grounds are free and given away on a first come first serve basis.
So if you want some free coffee grounds for your garden you can go to Starbucks and request a bag or call them first to see if they have some available and they'll freely give the used coffee grounds to you or anyone else wanting them.