I'm pretty new here and I was wondering the best way to make gold? I'm stuck in the Enigmatic Grotto where you have to fight Knug the Bonebreaker, and I assume that I may have a bit more of a chance if I have a third pet in my party...which requires 25k.

Thanks for any and all suggestions!

Edit: Also, I cannot purchase diamonds, so buying them to sell is out of the question.

Guide to Making Gold
Hope that helps!

I personally think doing missions is a good way to make small increments of gold that build up.
What you do is get 5 pets (of substantial levels), use all points in a certain stat per pet (ie one pet for Strength, one for Intelligence, one for HP, etc), then send those pets on certain missions that fit them best at Esior.