Besides the pattern, you just need cross stitch fabric (the pattern should tell you what size), needles, an embroidery hoop, and embroidery floss. It's a pretty affordable hobby until you're finished with a project and need to frame it. Even so, you can find affordable frames at Ikea, Michaels, and Jo-Ann's (especially if you save coupons). If you don't want to frame, check out this tutorial from EPBOT about putting your finished piece on a wood backing.
Bombastitch. Patterns are in the $4 range and are emailed to you within 24 hours (often much faster). She also offers complete kits with all the pieces you need! No trips to the craft store necessary.
Wee Little Stitches has a whole collection of your favorite groups in tiny stitches. Seriously. Batman villains, Watchmen, Shaun of the Dead, Princess Bride, all the Doctor Who incarnations, and Harry Potter are just a few of the designs this seller offers. Patterns range from $4-9.
The Crafty Companion has these and options from more fandoms. Patterns are $3 and up.
There are even some FREE patterns out there you can download and use.
Dork Stitch blog.
Han Solo sampler for no cost at all.
I'll see you at the craft store.
Oh, and my tauntaun head so far:
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