Well given the massive cost difference between markers and pencils for one, plus the fact that markers often require special paper to prevent bleeding into the paper. I'm going to go ahead and say you should switch to pencils for colouring.
For one thing, pencils are a lot more flexible in their use and can be more easily layered on top of each other while also simply applying more or less pressure will change the application, which is good when it comes to shading and highlighting your drawing.
And while the good ones are pricier, they're not as excessively priced as markers. And there's always Ebay too, I managed to bag about £100 worth of pencils for under £30.
Just some food for thought Solar.
Sorry if it sounds harsh but I'm only trying to help you here. Markers aren't exactly something I would be using if you're still learning. But what you do is up to yourself in the end.