Until you join the min/maxing brigade the game provides you with a free stock ship that won't be spectacularly powerful but will do the job.
Depending on your prefered ship type these will even be (soft) canon ones.
Slower Cruiser with the best surviving abilities: Sovereign class
Average fast science ship with good utility abilities: Luna class
Fast damage dealer escort: Prometheus class.
Each of these ships has a more powerful pay version in game, but as I said, to play and win 99% of the mission content those free stock ships will be good enough.