I have discovered the most wonderfullest crafty supply ever.
When I first started making resin jewelry, the first glitter I bought was by Crayola. I got it at Target. It was cheap and bright and the flakes were big and it was perfect for experimenting with.
Then, when I decided I really liked working with resin, I moved on to Martha Stewart glitter. They have this awesome set of 24 different colors at Michaels for like $29. You can also get it online on the Martha Stewart website.
Ok but then, I found this website... and all they sell on this website is glitter. TONS of glitter. In like a billion different colors. And different sizes. And some made of glass. And some made of little tiny spheres so they look like cupcake sprinkles. And it's just totally sparkly and magical.
It's called Art Glitter.
The website is kind of jumbly and hard to read/find things, but really the only page you need to care about is this one: http://www.artglitter.com/retail/Rartglitter.html All the colors!!! (OMG there are SO MANY.)
What I love is that you can go to CreateForLess.com (my new fave craft supply.. supplier) and buy Art Glitter in little sample kits for like $11, and then if you find a color you ADORE, you can go back to CreateForLess.com and buy a bigger jar (0.5 oz) of it for like $4. Which I have done. Because I am addicted. It's kind of like crack.
So I highly suggest this product, especially if you like sparkly things. And you don't have to use it for just resin (although it's excellent for that)! You can use glue and decorate stuff with it, because let's face it, anything + glitter = better.