This one just Stickles on the plastic/metal lid and takes no time at all.
For this one, I used a permanent marker to color the inside of the lid purple, then added purple Stickles on the top. I cut the A from a sheet of adhesive rhinestones I found at Jo Ann's and adhered it first, then added the Stickles around it.
These were especially easy and you could make a lot of them very quickly. Fill them with mints or little candies and you're set for a big gathering.
I found the favors at The Flower Factory, but I'm guessing you can find them just about anywhere.