I was wondering if anyone could recommend a good place to purchase geocoins? Are there any manufacturers and/or dealers in Maine? I'd prefer to give them my business. I'll be out in California for a big race in two months, and thought it'd be fun to leave one out there and make the goal to get it to a cache I'll be planting soon near my house.

There aren't any geocoin makers in Maine, nor dealers. There is a forum on Groundspeak dedicated to coins, trading, and selling. There is a pinned topic with geocoin manufacturers/retailers. You can find that page at:
http://forums.groundspeak.com/GC/index.php?showtopic=116800

I have some Maine International Geocaching geocoins available. All the details are in another thread here (http://www.geocachingmaine.org/forum/showthread.php?t=3031).

If you're interested in pre-made items, I've bought geocoins from a company called Geoswag (http://shop.geoswag.com/shopsite_sc/store/html/).

They have quite a variety and their prices are competitive.

If you want to create your own coin, try Oak Coins (http://www.oakcoins.com/).

This page has a great list of resellers.

http://www.geocaching.com/track/geocoin.aspx

I have bought some from http://socalgeocoins.com

Nice people and they have some fun designs.

Ebay has been good for me so far. No problems.