What if she does not claim the $150 on her income

To claim the day care credit, You have to provide the IRS her SS# and the amount you paid her. If her total  income is so low that she does not need to file a tax return, there's no concern. If she does file a tax return, the IRS computers will catch the missing $150.

Well I have copy of checks where had to pay a friend on weekend I’m going to need friend SSI number.

Yes, if you plan to claim the money you paid him/her for the day care credit.

Is the daycare credit a set amount or depends on how much is paid in

Depends on how much you paid. If you have one kid there is a $3000 limit on what you paid counting. If you have two or more qualifying kids the limit is $6000. The tax credit is somewhere between 20 and 35% of what you paid (up to the $3000/6000). See <a rel="nofollow" target="_blank" href="https://www.irs.gov/pub/irs-pdf/f2441.pdf">https://www.irs.gov/pub/irs-pdf/f2441.pdf</a>. It is a non refundable credit (unlike EIC) and can only be used to offset an actual tax liability.