Well that seems very underpricedMaybe not sell them. Maybe if you already have the items you could receive a message like
You already have [Item]! You have received 5 points and 10 experience!
The reward could change depending on the rarity of an item.
Common - 1 points and 10 experience
Uncommon - 3 points and 15 experience
Rare - 5 points and 20 experience
Legendary - 10 and 25 experience
Mythical - 15 points and 50 experience
Is this scale fair? :)
I also want to point out that you should just get points
Not exp
Common being at 5
Uncommon 10
Rare 25
Legendary 50
Mythical 100