A marketing consultant should be able to provide you with a statement of work / estimate for the services you are requesting. Strategic marketing plan development is normally a higher hourly rate (ranging from $150-$250/ hour). A full service consultant generally charge at least $90 to $200 per hour, lower hourly rate for strategy + implementation and higher rates for just strategy development. As yourself, is the engagement simply to develop a strategic marketing plan or to hire a professional to help in implementation of the plan?