Ooooh! Pick me! Pick me! I have a lot of experience with this one!
If someone is selling them, yeah I’d buy one. (Absolutely do not post it publically if you do pirate it…that might get you in very hot water, and word will get back to the designer eventually. It’s a remarkably small world…the internet.) If it’s a freely shared thing, I’d give attribution if I modified or used something of theirs in one of my designs, or link to their web pages.
Lots of folks make money from the advertising on their sites, particularly if they’re sharing stuff freely. Those clicks on the links to their sites actually bring them revenue. So it’s considered polite to send people there if it was their original idea, even if you modify it for your own uses.
Never sell or give away someone else’s design without working out a licensing agreement with them first. I’ve had people ask to give away physical copies of original designs for special purposes as promotional materials (educational use), and i didn’t charge them for it, and let them make as many copies as they needed without restriction, simply because they asked first. But most designs (even freebies) do have a limit on how many physical copies you can legally make…usually just a few for family and friends.
(And selling someone else’s design just causes headaches for everyone involved except the lawyers.)
That’s it really…just think of how you would feel if it was your design that someone was using, and then treat theirs the same way.
You’re safe making your own stencils, or boxes or stamps, if the design is yours. (Can’t copyright a box.)
For the same reason, there will be many iPhone stands, storage organizers, and coasters. Some of them are going to look similar after a while. Doesn’t necessarily mean the idea was copied…it’s tough to be completely original with household items because certain shapes just work well.
It isn’t going to stop people from getting mad about it though. Saw that a lot too.