The only problem I've had is whenever I have to buy health potions - an annoyingly rare drop and the prices get higher as you level, those can put a dent in my gold easily. I found some gear that increases chances of health orbs, though, so that hasn't kept me from surviving.. but I wish I could have a steady stock. :P I'm playing as the Plague Wizard; ranged + mage tends to be a little squishy universally.
ETA: Have you been buying from the Blacksmith? Because I can see needing a lot of gold for using him regularly for gear. I haven't actually bought anything from him yet.