A very quick usage note based on an error I see quite a lot.
“Economic” is an adjective that means “related to economics or the economy.”
“I had to sell my house for economic reasons.”
“Universities that invest in sports enjoy certain economic benefits.”
“Economical” (note the last two letters) is an adjective meaning that something is affordable or doesn’t cost or use a lot of money.
“My new compact car is very economical.”
“I replaced my old light bulbs with more economical fluorescent bulbs.”
“Switching to solar energy is a very economical choice in the long run.”
You can also refer to a person who doesn’t spend a lot of money as “economical,” but I think this is a bit less common and I tend to avoid it.
“Josh is a very economical shopper.”
Just to complicate things, the subject you study at university is “economics.” Note the final letter.
“I took an economics class last semester.”
“I need to buy an expensive economics textbook.”
Quite a lot of students forget that final “s” when they write personal examples in their essays!