Instead of the locker item? it would have to be better than those things then. Locker items are pretty epic to just let go.
Based on yours, I would propose these:
+1-2 base damage per level.
Starts with an extra mana potion, and an additional spawns on map.
Starts with an extra HP potion, and an additional spawns on map.
Starts with +10 HP and an additional HP booster is on the map.
Starts with +2 MP and an additional MP booster is on the map
Starts with +10% damage, and an additional attack booster is on the map.
Every level requires 1 less experience to attain, and spawns 3 extra gold piles.