Sales contact leads

I need a data collecting exercise which wont necessary be a difficult exercise but probably a time consuming one. I need the individual to pull together some data which includes contact details of potential clients so we can send out a mail shot across a vast audience to help generate interest and new clients . If this is a successful project then more projects similar to this will need to be carried out .We will go for the cheapest rate given . Our budget for this project is £10-£50