Hello,
The import process is easy, there is a tool and if all OK it will be done automatically, probably in less then an hour for all of your object types (Accounts, leads, contacts....)
It takes some experience to normalize the data and to prepare it in form to use maximum of it. Then the challenge is to adjust the views and layouts of your salesforce instance to show the data in a way that will be effective for you and your sales reps.
To implement some processes, dashboards and reports so you really enjoy the benefits of sales force.
As described, considering you already have the data in excel spreadsheets my offer would be:
200USD plus Freelancer fees, and i assume this will take about 10hours in 2-3 days all inclusive (getting access, communicating the details, understanding your organization, import, corrections, layouts and basic training for you and your staff).
You pay at delivery, if satisfied. Money back guarantee.
When you'll have better requirements i will be happy to quote to implement and adjust salesforce to best fit your needs at rate of 25USD/hour plus Freelancer expenses.
I have over 15 years of experience in software engineering, dealing with salesforce from 2009. I hold Bsc in Computer Science and MBA in Sales and Marketing. With large experience in software development and business management, so i believe i can bring you overall value to your business processes.
I wish you choose the best bid for you.