As a phd student, how do you get help with childcare costs? I desperately need this, please give me as much information as you can.

You don't.
Although if your partner works you may be able to get help if you purchase childcare vouchers directly from your wages....
I can't tell you any more about this as I don't know, but I'm sure if you google....

I am a single parent. Can anyone tell me of any way i can get help with childcare costs while doing a phd

Most universeries have means-tested burseries to help with childcare costs. You should contact your university fincance/admin people and ask about that. That is the only help available for graduate students (as opposed to undergtraduates).

I didn't qualify as my husband works. I got a grant which I spent on childcare.