There are lots of ways to justify a Prince being a PC.
All princes spend some years adventuring, to get it out of their system and learn valuable skills.
The PC ran away from the court to become a Ranger, scandalising the court, so has been disowned
Prince by day, ranger by night, the Court don't know he is a ranger, but he takes long breaks, wanders around the countryside and returns to Court
He is the third or fourth son, nobody knows what to do with them, they can't rule otherwise they might want to kill their brothers, so the only options are a life adventurous or a life clerical
The Royal family come from a long line of Rangers and all Princes spend some time as a Ranger, part of becoming a man. Even better if the Prince doesn't really like the outdoors.
The Prince decided to become a Ranger and has been shunned by the court. Every so often, the King sends someone after him to drag him back ...
Third Prince became a Paladin, so Fourth Prince could only be a Ranger and he is annoyed that he couldn't be a Paladin (Ah, he is First prince, didn't see that, perhaps Second Prince became a Paladin instead and really annoyed him)
As for freebies, he would definitely get good equipment, maybe a magical sword. other stuff would depend on his relationship with the court.
If he is a secret ranger, then he couldn't really call on any favours, unless he got into real trouble.
He might be rich, so would have access to a lot of gold.
He might try to call on people's help, as he is a Prince, but do they believe him?
He might try to call on people's help, as he is a Prince, but do they care?
He might have some powerful friends, perhaps the local Duke, or Commander of the local forces.