so, i had an idea for a modded item that could be used to set up a taxation system for my medieval neighbourhood.

it sounds simple enough to me.

it would be an object you place on a lot, that would activate once daily and subtract a percentage of on hand money, sending it to a tax collector, noble, the king (ie, another household in the neighbourhood)..
it needs to be able to set the percentage and payee, and after that it would be "set and forget"

where would i start for making mods like this? are there any beginner tutorials or up to date information on how to make scripted objects for sims 2?

any help appreciated and thanks in advance

Echo's Making Your First Custom BHAV tutorial can get you started working with BHAVs (the code that TS2 objects use for their functionality). It assumes no prior experience with programming, but it does assume reasonable familiarity with SimPE. Have you ever cloned an object and gave it an unique GUID before?

Your project may be a little ambitious for a beginner's project. In which case, you may have to take baby steps first. You might be interested in some mods by monique, such as the Automatic Payment Mod which does something very similar.