Her prices are very reasonable - many clipart singles (like the 2 cupcakes above) are only $1 each, and they're super-high quality. You get both a JPEG and an PNG file, which I've recently learned is the transparent version. (see: Old dog, new tricks). And, she regularly offers freebies. There are tons of themes, and they'd be perfect for coordinating a birthday party invitation, cupcake toppers, etc. You can buy clipart directly from Jessica's website or through her Etsy shop. Be sure to sign up for her newsletter, where you can get discounts, and see her latest work.
Here are a few more of my recent downloads:
I've never met Jessica, but I have a feeling we'd get along just fine.
Look for these to start showing up on my blog, and in my shop. I've already used the two birdies on a branch to create a new Etsy header - you can check it out here.