This is a great question, I have been wondering the same .
I have this in mind :
Tim Holtz Distress Ink Reinker Refill Ranger U Pick 10 | eBay
As well as this:
Tim Holtz Distress Marker Tube Set 37 Pkg 3 5"x7 35" | eBay
Any advice is welcome *
Thanks for starting this thread Sunday !