Graphics is my hobby. I enjoy learning new concepts of design and playing around with images and making my own banners, ads, etc. I used to exclusively use free software like Gimp and Inkscape, but now I LOVE the $50 monthly fee that gives me just about every Adobe product under the sun (Creative Cloud).
is a place I found early on that has free packages of vector graphics, and other cool things someone like me just starting out can use. Plus, their items can be used for commercial uses.
About once a month I find a great deal for $10-$15 that gives me thousands of images to play with or brushes for Photoshop (it's kinda like digital stamping LOL).
Their customer service is great and the download link arrives right away.
If you're not sure what a vector graphic is and why should care, I have a blog post explaining in simple terms what they do: http://eawestwriting.blogspot.com/2012/05/vector-graphics-vs-jpgs.html
They have a St. Patrick's Day active deal for only $12 that gets you over 100 vector graphics and icons. With a vector you can grab the shamrock, pot o gold, rainbow right off the sheet, put it on say a banner for your "Lucky Deal" with you book cover image and some words, and you can resize it or change individual colors etc. Today I bought that, the ten premium tutorials for $9.99 (still learning my Adobe products) and the mythological creature set.