If i have no income other than 300 dollars from tutoring for the whole year. can i contribute that 300 to my roth IRA? thanks

Is the Self-employed income?

yes it is

Never mind. It's under $400 so you are OK.

It is now past the deadline to make a Roth contribution for 2018

yes i meant roth 2019

If your income goes over $400 by Dec 31 you'll have to reevaluate.

ok thanks

a contribution of no more than $300 would be OK no matter what you make, so you can put that money in now. If you want to maximize the contribution without exceeding  you have to know your income as of Dec 31.

Yes, you can.