The lights are on
Very much what the other guy said. It is not so much p2w as much as it is pay to access. First i would say that TOR is built around the PVE experience focusing on each classes story. There is some PVP but it is nothing crazy special. So regardless of paying or not you are never really going to be winning at this type of game.
Paying or using coins comes into effect mostly at level cap. If you dont pay you are extremely limited. You can only run so many PVE instances, PVP battle grounds by default and will need to spend coins if you want to do more in a single week. If I recall you are also limited in some of the gear you can wear (no epics). All of this sounds bad and it really is a bad F2P model. However if you are just looking to experience some of the story as you do some leveling the free version is actually very good. Many people have played up to level cap for free and then subscribed when they got there and had very enjoyable experiences.