After having a few really awesome suggestions from members here, I will be implementing a few changes to the Marketplace to make it a lot more user friendly. Here are all of the features I should be adding within the next few days:
1. Below each forum name in the Marketplace, add a picture link that does the following: Go into the specific board AND only show threads with prefixes that match the picture link. For example, have a picture of the Khaini symbol below the "Selling Board" board link. When you click on the Khaini picture, you enter the selling board and only see Khaini threads. This same effect will be added to Buying Board.
2. For price check board, the same picture links will be posted, but instead it will take you directly to the thread represented by the server symbol you clicked on.
3. Inside of the Selling board and Buying board, replace the current menu system at the top of the threadlist with picture links. A chinchilla picture will signify "Choose all prefixes".
4. Thread prefixes will be clickable. For example, clicking on the Scania symbol in the threadlist will lead you to a page that only shows Scania selling/buying threads.
If you have any other ideas for changes to the Marketplace, please let me know!