itemtrade.bin for the shop contents, npc.bin for npc job type.
It's easy to figure out, you just have to match references up. I was the very first person to have access to these on the original Xor and I didn't find it difficult to figure out what went where so neither should you.
The bins all follow a logical referencing process across themselves. The best way to learn is to study them instead of asking for help over simple things. If you struggle with understanding the bins then you're going to struggle even more when it comes to the more complicated stuff.