Hello Aukustus. Instead of working on my own project tonight I decided to work on your game.
I idealized a new interface for buying and selling items.
http://tivohdmg.photobucket.com/albums/v698/EFileTahi-A/Newinterface.png?t=1399068870I've merged regular items with special items to make trading easier while at the same time making item comparison faster. I added color codes to make reading even better (for common and rare items or common vs enchanted items) and justified the prices in a column as I often loose my eyes to items states when I'm looking for price tags; having prices in a column also helps us identifying budget items from powerful and expensive ones. But the major change is actually the way you operate the interface. I believe that having a "selection row" controlled with UP and DOWN arrow keys makes the whole item selection easier. In the image we see a gray row and this row indicates the current selected item ready for purchase.
The same concept should also be used for selling, where the items & equipment would be shown in the same window with the same configuration as presented in the screenshot. Consider using the row selection in every option screen as it works so much better for there is no need to interpretation and no looking down to the keyboard for each option we choose.
Please tell me what you think. If you enjoy this I can rework other parts of the game's interface for you.
Take care and continue with your good work. I'm actually enjoying the game a lot now, with the 'Rest' option revealed