Doing a new run with some new mods compared to my previous including (until now at least) Transport drones, While moving to add higher tier supply items to the depot I realised the supply value of many items is off. To give just a couple of examples:

consumer essentials: 1unit/125coin/75 supply - normal
consumer impliments: 1unit/1coin/1 supply - definitely not normal

Many other regular items such as roboports and yellow belts also show the same. Resyncing and loading the last save of my previous run has all the correct values so it was definitely a mod conflict somewhere, usual 5x5 sort through identified the Megline fork of Transport drones as the culprit.

I've had a dig through the files of both mods, now I'm no programmer but reading the scripting I hope is giving me half an idea of what's going on. Within the Colony Builder mod script_libs is script-trade.lua which if I'm reading this right is what determines the "price" of the items?

My best gues is that Transport drones is somehow over-riding those values, how I couldn't begin to say. Unfortunately Klonan the original modder is less active these day but I'll drop a copy of this over there so those working on forks are aware.

For now I've disabled Transport drones so at least my economy doesn't die on it's backside for lack of supply. May be worth adding to the incompatible list.