I'm not sure when the save editor for Inquisition will be ready. But until it is, I have found some helpful exploits while searching for getting a nice boost in Inquisition.
This works on Xbox 360, Xbox One, PS3, PS4, And PC if you're using a Controller on PC.
Infinite Gold / Material Duping / Maximum Influence
This can only be used on Crafting Materials as far as I've noticed, this is also limited to armor / weapon crafting materials. What you do is take the Material you want to dupe and move it into your Valuables in the Menu, go to any shop keeper and go to sell. Go to Valuables and you'll see the materials there. Hit A + A + Y really quickly, you'll notice a second prompt for selling pops up after the second A. Hit A again. Now go to Buy and go to Buy Back, you'll see double the amount of the material (Must have 2 of said material to start duping) You can also use this to dupe more than the desired amount to keep selling for gold! :D
Quick Steps -
1. Move Desired Material to Valuables.
2. Go to Valuables when selling at a shop, Hit A, A, then Y really quickly and A again.
*(X, X, Triangle on Playstation)
3. Buy Back all the materials you just sold.
4. Repeat as much as desired
As for Maximum Influence, it's done the same way as Material Duping, however it can only be done after a certain point in Skyhold, eventually a Merchant will show up in the same courtyard as the Horse Pens / Blackwall who sells items that raise your influence. He only sells 10 each. However, If you buy them and without leaving the store, go to sell and sell them back, you can continue to repurchase and resell them constantly. Each time will garner you influence, however you wont see it pop up until you leave the shop. If you do this on the most expensive one at the very top, doing it about 7 - 8 Times will Maximum your Influence at 20.
EDIT -
Infinite Skill Points for Main Character (Thanks 13Dannyboy13)
"Another exploit you can use for your main character is the unlimited amulet of power in crestwood. You must do the story past draining the lake though first, then when it's done (clear skies, not raining anymore) the boarded up locked door right near the fast travel stone will be open, inside you can loot for an amulet for your main character, and another random item. TAKE ONLY THE AMULET, and leave the other item, then fast travel to another zone, skyhaven etc. and then fast travel back to where you got the amulet, since you only took one item it will have respawned and you can repeat the process as much as you want for skill points."