How do you end up not having cash? Do you dismantle a lot? Or do you buy expensive items in stores?
I just loot pretty much everything and 'clean stacks' once in a while, having no stacks bigger than 15 to keep weight in check. And I never dismantle anything unless it gives some really rare crafting component. Dismantling is expensive, the only stuff I dismantle is socketed items that I want the runestones or upgrades back from. Repairing is also almost never really needed, it is much cheaper to craft a new item instead, because it gets 100% durability as well that way. When in the field, repair kits fill the need. The big money for me in Velen was by looting all the bandits and robbers along the way, and selling their weapons which go for 50+ a pop. Animal skins also sell for good cash. Horse racing and brawling also net a few thousand all together if you place maximum bets. The Baron in Crow's Perch also offers some nice quests for money. And this is just lowbie-Velen I speak of...
Sitting on 10k in cash atm and no real intention to spend much of that, everything you need can be found for free (I am level 15 now and main quest is at Novigrad, so not too far ahead of you story wise it seems). Maybe a respec potion somewhere along the road...
Griffin armor is awesome. Signs become a lot more powerful. I'm burning ghouls with two Igni's now
Oh, side note, in case you haven't noticed, there is going to be a lot of backtracking going on. I found level (??) enemies in the area as a level 15 and some quests even range above 30 and are still in Velen. So you may want to forget about the full clearance itch for now