ButlerFord45 made a good point in one of his posts (OK, he made a bunch of good points but we're just looking at etiquette now).
If you go to a shoot and someone lends you stuff you need to offer something in return. Pay for the ammo (probably won't be accepted but money does talk to some), clean the guns, walk their dog, etc.
On my first trip the club allowed me to shot free as I was a first time shooter. My mentors provided everything from guns, to ammo to leather. They refused my offers to repay them so I am casting them some 250 grain 45LC as a gift. Something they can use and a way for me to say thanks. Supplies (powder, shot, bullets) are always being used and usually it's more the thought than the actual object.
And, hopefully, some day you can return the favor to a new shooter of your own.