Linkedin sales navigator free trial for a month and get your first clients and then you will be able to pay subscription fees. Free trial has 20 inmail messages to contact clients directly and awesome search filters
OR
Join Linkedin groups where your prospects are members and you will be able to contact them through these groups.
Maintain some decent level of professionalism and make sure your profile looks neat. Much better if you have more than 500 connections and endorsements.
PM for more tips. Lol.
At any rate i hope this helps.