I am breast feeding single mother, I work 3 days a week(freelancer). I have to work to provide for me and a baby, I pay babysitter when working.
-How do I get out of Jury duty and be truthful?

Tell them what you told us.

You can say that, but it's not guaranteed to get you out of jury duty. After all, if you are working three days a week, that means that there are four that you aren't that you can do jury duty on. And breastfeeding is not an automatic reason for dismissal, either.

Best you can do is be truthful about your situation and see what happens. I've been called for jury duty twice, got empaneled once for four days, and the second time just hung around the courthouse for a day before they sent us all home and told us we had fulfilled our obligation. If you can afford a day, your best bet may be to go and just hope that you don't get picked that day.

Yes you can try, but people who work 6 days a week, don't get excused, just working does not get you out of it.

And with breast pumps and the such, they may not see this as a excuse either.

Write a letter to the court and explain everything you've told us here. Normally lactating mothers are exempt from jury duty.

I was called for duty many years ago, I explained that it would be a financial hardship on me. They did not make me go. I don't remember the exact details as it was 20 years ago.