The value of such character charms is hard to determine, it would be best if Yu Liang personally oversees the evaluation. Leaving it to unmanned trading might be a bit of a stretch.
Enhancement type character charms, such as "Strength", "Speed", "Defense", "Endurance", are priced at 10 grass baby coins. These are often rewarded in the world of Monster Tale, so their value is easy to determine.
However, Li Huazhao expects that there would rarely be anyone willing to trade their restriction type or enhancement type character charms for grass babies, as these charms are generally more valuable and harder to obtain than attack type character charms.
An E-ranked grass baby is priced at 10 grass baby coins, while a D-ranked grass baby falls within the price range of 50 to 100 grass baby coins, depending on if it has exceptional traits.
This pricing closely matches the probability of mutation, so Yu Liang doesn't need to worry about a market crash for the grass babies.