One of the questions most asked of a certified Salesforce.com consultant is what is your rate for Salesforce consulting and what fees can I expect? I can only speak of what I’ve observed in the Dallas market for Salesforce.com consulting rates, but the spectrum starts at $150 an hour for freelance consultants up to $300 or more an hour for the larger Salesforce Partners. I suspect Dallas Salesforce implementation rates are cheaper than many parts of the country. Travel is a reimbursable fee, and some firms charge for "seat time" on a plane while traveling (lost billable hours is the argument).
Salesforce consulting rates can also vary by the type of work requested. Consulting and native configuration would typically be quoted at a lower rate than work requiring custom development (e.g.: Apex code, Visualforce pages, Sites, and integrations). Custom development can easily run 50% or more per hour than native configuration. The skills are simply in greater demand.
Data work, whether de-duping records or importing data from legacy systems, and custom code development is typically not fixed bid, but charged by the hour. My experience is that this type of work can rarely be scoped accurately to fix bid.
With a strictly defined scope, native configuration (configuration accomplished through “Setup” in Salesforce) can be fixed bid effectively. The cost and time to configure Salesforce is dependent on the amount of customization required (e.g. how many custom fields, how many escalation and workflow rules, how many reports and dashboards, etc). The time required to accurately gather these requirements can vary drastically based on the complexity of the business process you are trying to incorporate into Salesforce.com.