First, before you begin the process of hiring a Social Media Consultant, you need to address a few areas:

• Figure out what you want to accomplish via Social Media.  Do you want to generate sales?  Increase brand awareness?  Establish thought leadership for your CEO or company?  Connect with donors?  Giving some thought to what you want to accomplish via your social media efforts will make the rest of the process smoother.
• What are your human resources?  How many people can work on your social media efforts?  If you have a team of 10 at the ready, then the amount of assistance you will need is far less than if you are the only person for your company that will be handling your social media efforts.  Know how many people can work on your social media efforts and how much time they can devote, because if you plan on executing a Social Media Strategy that will require a team of 5, and you only have 2, that shortcoming will have to be addressed either through hiring, or outsourcing to the agency/consultant.  Either way, it costs you money.
• How long is your project going to be?  You probably can’t pin this down exactly without talking to the consultant first, but it helps to give some thought to this.

When you contact a consultant or agency, they should be asking you questions as well.  They should want to know why you want to use social media, what are you trying to accomplish.  If they try to give you prices or push you toward using a particular tool without asking you questions, that is a red flag.  They really can’t give you prices until they know more about your company, your resources, and what you are wanting to accomplish.  Even if you contact them and tell them you need prices on creating and launching a blog, they should still ask you some questions to determine if you do need a blog to reach your intended business goals for your social media strategy.