Is my 3 year old foster child entitled to any of the stimulus checks? How much money per stimulus? The software wont include him in asking for a credit on his behalf?

 Yes, dependents claimed that are under 17 years old will qualify for the stimulus checks. 

It would be $500 for the first stimulus payment and $600 for the second stimulus payment. These payment amounts are subject to income limits. For income over the limit, the credit is phased out. 

To see the eligibility rules for the Recovery Rebate Credit, click this link: How do I claim the Recovery Rebate Credit? and scroll to the drop down details for eligibility. 

To input your details, follow these steps:

1. Go to the search box and enter stimulus. Click the Jump to link.
2. Answer Yes.
3. At the next screen, Let's double-check the amount you received, answer No to edit the first-round and second-round amounts.
4. If no stimulus amount was received, enter 0. An amount must be entered in each box. When finished, click Continue.

For more information, see: Recovery Rebate Credit — Topic B: Eligibility | Internal Revenue Service.