Spelljammer is much more than just adventure and killing pirates. Sometimes running a business (or being a pirate) is your only form of income. Say you (a group of pirates who are down on your luck and have nothing to your name, run across a whaleship crewed by humans. Well you captured the boat, have the crew in irons and are gathering valuables off the richer passengers. If your lucky you might get a couple thousand gp worth of stuff, but ship repairs, ammo, new crew, food and taxes? Not going to cut it. Turns out that whaleship was stuffed to the brim with goods such as tobacco and rice sent off to some war effort. You could have gained at least 10000 if not more right there. That merchants wife can now afford to get a better necklace that you stole.
If you can't think of anything use Auroras Whole Realm Catalogue for specific things. It can give you a price on useless knick knacks, to goods and items no other books can help with.
Example: tobacco is 100gp per pound, 2000 pounds are in a ton, (do your charisma checks for a bonus in buying and selling) boom 200000gp later, (life savings, crew pay, and everything you own) and you have 1 ton of tobacco. Now comes the adventure. Finding a place to make a profit. And screwing them over for extra cash? Might just create another question to clear your name (of this crime at least)
Examples of exotic goods for AWRC: Chilis go for 100gp/lb whole, or 20gp/oz ground.
Cigars are 10gp per cigar. Where as bulk tobacco is 100gp/lb.
Cocoa powder and fagara sells for 100gp/lb
Tea goes from 20gp/lb to 50gp/lb
Vanilla is 100gp per bean
Pecans are 150gp/lb
Dried pineapple is 300gp/lb
Coconut is 10gp/fresh nut, 50gp/dried