RP is normally recovered by spending money at The Blue Moon Hotspring in Rune Factory 5 or by purchasing food at the Lackadaisy. There is a method to recover RP without spending money or consuming your food items in the game.
How To Recover RP Without Spending Money in Rune Factory 5
Blue crystals and blue flowers can be found throughout the world in the game. These objects can recover a decent amount of your RP. Breaking or cutting two should restore a sufficient amount of RP to do daily chores or head straight into battle.
The best part is, these crystals and flowers are in common locations. Fast travel to either the entrance or the first floor of one of the main dungeons in the game and you are guaranteed to find one of these objects nearby. Smash/cut at least two and your RP should substantially recover without spending money.