I agree with the above people. Clerics are
NOT made to be used as moneymakers. They
ARE made to support and to help people. If your looking for a quick leveling character clerics are usually good to use. However, if your wanting to be a tanking cleric or somebody who enjoys attacking then don't be a cleric.
Clerics are for support to a party with the ability to assist if they have time to or defend themselves if you argo monster from a tank or DD.
If you want to use a character for leveling up, use a archer or mage. I used an archer till level 10 and didn't have to put a single peice of copper into the character. If you just put Stat points into strength you should be able to kill without using any skills. But that is my thoughts.