Possibly as uncommon as the salesmen and such
While cautiously walking through the forest a Nin dressed in blue emerges from some of the trees. Expecting some sort of challange you reach for your weapon, but upon lightly gripping the hilt, he says, "Worry not, for I am a peaceful Medic Nin wandering the forest healing injured creatures and Nin.. Well that is my dream at least, yet I lack talent and sometimes end up harming what I wish to heal. You look in a rather healthy state, would you mind providing practice with a healing jutsu?" You discuss the apparently jutsu and find it can heal you beyond perfection
Allow him to Practice.
5% Chance - You watch him make hand signs perfectly, before his right hand glows with the blue aura that you know is a healing jutsu, he lightly taps you on the forehead and you feel a cool, comforting, feeling flow throughout your body.
Health Restored to 200% of max
25% Chance - You watch him make hand signs almost perfectly, before his right hand glows with a slightly off blue aura that looks close enough to a healing jutsu, he lightly taps you on the forehead and you feel like you've just had a spoon full of not-bad medicine.
Health Restored to 150% of max
30% Chance - You watch him make hands signs well, before his right hand glows a green, that your not quiet sure is properly a healing jutsu, he taps you on the forehead and you feel quite alright.
Health Restored to 100% of max or if so already, no effect.
15% Chance - You watch him make hands sign amataurly, before his right hand glows an orange, that your don't think a healing jutsu, he taps you heavily on the forehead and you feel a bit of a bump.
Lose 25% of current health
10% Chance - You watch him make hands sign sloppily, before his right hand glows a red, that your not quiet sure is meant to be healing jutsu, he taps you heavily on the forehead and you fall to the floor with a thump.
Lose 50% of current health
5% Chance - You watch him make hands sign sloppily, before his right hand glows a deep red, that your not quiet sure is meant to be healing jutsu and prepare to run but he taps you heavily on the forehead and you get knocked to the floor rather painfully.
Reduce to 5% of max health, gain (level * Max health) gold
(Or lose one turn)
Tell him you'd rather play it safe.
50% Chance - He agrees that there's a bit of a risk involved, and you leave him to heal a little bird on a branch nearby. As you walk away you see that bird flying flawlessly.
50% Chance - He agrees that there's a bit of a risk involved, and you leave him to heal a little bird on a branch nearby. As you walk away you hear a loud screeching, and think you made the right choice turning down his offer.
(Note: Results of turning it down don't effect anything, just to add effect.)
As stated, not meant to be a common event, and is meant to give either relief from healing costs, or be a pain to costs.
All your constructive criticism is welcome.
Edit: Decided compensation is a better idea, so changed it to that