If you have any higher level wizards on the same account, you can do higher level dungeons or such, get good stuff, put it in your shared bank for your lower level wizards to sell.
If that can't work for you, you can do haunted cave, goblin king in colossus boulevard, or any major dungeon... to get stuff to sell. I find that in team up there are always good wizards. Of course, questing would be one of the best ways to get gold.
