Just curious. I am sick of fast traveling between 5 cities to sell my stuff cause the damn merchants run out of money. Is there a better way?

If you're already bleeding the merchants dry of barter money, you're technically making it as fast as you can...without cheating.

Edit: The method I use is getting the TG fences in place asap.

well, you can grind the woodchoping block

You could invest a few perks into Speech so merchants have more money.

You could sell your stuff, quicksave, punch the merchant and quickload. This resets the merchant's inventory and gold so you don't have to travel everywhere

Wait 48 hours and merchants will restock or you could invest in speech perks to expand their gold.

Thieves Guild all the way if you dont want to put perks into Speech,in my opinion. As Nefarious One already mentioned,get the fences in place asap and eventually you will be rolling in the gold lol =) Especially when it gets to the point where they all have 4k to barter with. Since all the fences are located in,or near,major cities you can combine them and regular merchants to make huge profits in between adventuring. Also,the icing on the cake are the travelling Khajit merchants,who will eventually have fences with 4k to barter with aswell^^

You'll find yourself hard pressed to find a place where you cant sell the contents of your inter-dimensional bag^^ Unless you're in Morthal that is lol