There are two rewards going to miners to reward them for their hashing power they are using to process your transactions. The one is the
miners reward and the other the fees. I always compare this to the waiters in a restaurant. The miners reward, is the waiters's salary and the
fees are the tips. In future the miners reward will fall away and the fees will be the only reward. ^smile^ So, pay your tips, it's actually not as
much as you might think... a few cents.

that's clear and simple, Thanks!
so fees are basically money for miners, and miners earn that money by putting in the computing power that makes this cryptography works. And the tip size is completely irrelevant to the transaction size. no matter how much money you are sending, the more tips you pay, the faster the transaction will be confirmed, in general.