Zedwork

Im not sure if this is the correct place to pose this question, but is there any "special" way that shops are created if I wanted to create a shop?

Do you mean the chest shops?
You need to put the sign above the chest (which shouldbe best empty) with the following on it :
First line: the item ID or name in [ ] for example [dirt] or [4]
Second line: buy (amount) for (price) as price you can have i for iron, d for Diamond, e for emerald or g for gold. (This is the price for what you sell it and the customer buys) For example: buy 64 for 2
Third line: sell (amount) for (price)
third and second line are optional if you have at least one of them.
The fourth line should be empty and automatically add your name when you close the sign editor. If not you made a mistake and the shop did not get created.
Maybe Yes wick should add that to the help page for trading.
But I hoped I helped you.

Thanks Treiskaideka for the help.

Here is a very useful link with all item ID's and names:
http://www.minecraftinfo.com/IDList.htm

(You can not sell enchanted items or enchanted books with this shop system).