Cost Vs Worth Vs Value
Cost, worth & value are words that ESL students frequently ask about.
What something costs is directly related to the amount of money you need to spend to buy it.
Worth depends more on how important that item is to the person directly.
Closely related to worth is value. But how valuable something is tends to be set by public opinion. When there is high demand or limited numbers of something, then the value normally goes up.
But this being English language there are of course grey areas to all of this. But this basic idea should work for you most of the time as a starting point.