One of the best distributors of these stickers in the US is the company Paper Wishes/Hot off the Press. They also have a monthly club that sends you a set of 4 stickers (they call them "Dazzles") every month along with a selection of coordinating paper and embellishments. Here is an example of a stacked dazzle card:
These dazzles are available in white or silver today, but this blue holographic color is just for the club. If you look closer, you'll see that the main snowflake is actually three layers of snowflakes - each was mounted on cardstock, and I trimmed closely around them with a pair of detail scissors:
Here is another stacked card with a different pair of snowflakes:
Once you've used the outline of the sticker, you're left with the inner parts or "innies." You can use a sticky transfer sheet to use those parts as well - almost nothing goes to waste on these sticker sheets!
All of the blue snowflakes come from the Hot off the Press kit, along with the blue patterned paper and tag. The first sticker sheet and the "Merry Christmas" sentiments were brought back from a trip to England. The remaining paper is from a variety of older Club Scrap kits.
These sparkly cards are very shiny in real life, and are a nice change from the muted tones I've been using lately. Paper Wishes offers an e-book to help you learn more techniques using these really nifty stickers. Give them a try! They are inexpensive, and a great way to get embossed images without a heat gun.