Hi John,
Thank you for this question -- and I hope my reply is not too late!
In terms of dollars, it is hard to give you a specific amount without knowing details of the project, but it is unlikely that you will find a decent evaluation consultant with community assessment skills able to take this job for less than $8-15K.
Generally speaking, at the initial scoping of a community intervention project, evaluation should be written in for about 15% of your total budget. Any data-to-action effort at the community level will probably need to be mixed methods (i.e., a combination of quantitative and qualitative data collection); and qualitative research, such as focus groups and key informant interviews, requires more time and money than survey-based work.
For a community needs assessment, I would probably say 10% of your total Head Start budget for the needs assessment. I would strongly recommend allocating another 5% of the total project budget for some type of process evaluation and/or outcomes assessment.
You can find contract evaluators through the American Evaluation Association's website here: https://my.eval.org/find-an-evaluator
Best of luck with your budget -- and your Head Start program!
Sharon M. Wasco, PhD
Ask an Advisor, July 2021