Stop hurting my brain!

Hi guys! If you've read the other blogs my friends are doing, you probably know that a couple of them are doing Fantastic Facts! Or BIG words. Without even knowing it they have inspired me to do my very own one. Its called... (drumroll) Stop Hurting My Brain!
Filled with exciting riddles and brain teasers.
How does this educate you? It helps you concentrate and develope yourself to think more deeply about things. Here's your first 2 of the day.

Easy: What is as big as you are and yet does not weigh anything?

Hard: The person who makes it sells it.
The person who buys it has no need for it.
The person who uses it does not know he or she is using it. What is it?

Think you know the answer? Write it on the comments below.
Also look in next week for your answers and 2 new riddles.
Good luck!!!