You can also buy them off of Etsy. I'm in the US, and the only place I've seen them not online is Hobby Lobby, but they didn't have the flat base. I think Sug said she used to get hers online at Oriental Trading Company.
I've personally never tried it, but if you're going to use permanent marker I'd coat it with a less caustic, but heavy duty coat of lacquer before placing it in the resin (Triple Thick Glaze is what I used). I've done this with paper printed from an inkjet printer and the color didn't fade or smear. Resin is extremely caustic and will make ink bleed or fade. Heck, it even takes the measuring markings which are engraved off of my mixing cups when I mix resin! Send me a message if you need anymore tips! Good luck!
I have a shop on Etsy and have made over 250 sales in less than 2 years. The fees can be outrageous if you're a manic lister like me (e.g. 200 + items), but it's not too bad if you only list a few things and see where your shop is headed first. Many of my buyers are from outside the U.S. I only have 12 items in my shop right now as I'm opening a new shop on Etsy for plushies soon. We'll see how that goes . . . I believe Etsy is far more well known than any of the other handmade marketplaces, so it's best to start out there. My success, I believe, was to intense online advertising on CO+K, Twitter, Facebook, and my blog. I also held a lot of blog giveaways and had them advertised for free on Etsy Giveaways. It would also be a good idea to open an account on deviantART.com as you can do a lot of networking there and get the word out about your shop. Networking is key. I've made close contacts with the owners of two popular zombie themed sites (some of my products are zombie themed) and all I have to do is shoot them an e-mail and ask them to do a post on an item or my shop. So which ever site you choose, network, network, network!!!
Your things are awesome! I really like the banner in your shop, too! Everyone has offered very good suggestions. I love your idea of guerilla advertising! Another small thing you could do is make a blog button to put on your blog linking it to your shop, also include a text box underneath so others can "grab" it and post it on their blogs. Check out the Grab My Button, Share Yours thread. I have a link tab on my blog where I keep all the buttons linking to my friends shops and sites. I'd really like to add one for you!