No such thing as a daft question. We've all been there.
Likely it's the commodity type "Food Cartridges". These are low priced items, often for sale by Industrial system (not Agricultural ones), and listed under "Foods". Retails for around 50cr per ton, and in a basic Sidewinder two tons mission should net you some profit.
So, look on the Galaxy map for a nearby system with an Industrial economy. Also check the other starports and outposts in the current system, as secondary starports/outposts can have economy types different to the main system economy.
Some missions do require the goods to be stolen, so watch out for those as they are a lot harder to fulfil and you will need a cargo scanner to check what other ships are carrying before opening fire.
Finally, I do sometimes find missions for commodities (the "fetch this" missions) where the commodity is on sale locally. So I accept the mission, buy the goods, complete the mission. Simples.