Mercentile is one of the toughest skills to increase especially if it is a minor skill but there is a very easy and effective way to "master" mercantile. Simply gain access to the arcane U. and create a fortify mercentile spell 100pts. 1-3 secs. The spell is very cheap to make and cast , simply cast the spell before speaking to ANY merchant and you will be able to invest 500 gp , getting you better deals. Same can be done with speechcraft , security etc. NOTE: with the armorer skill , you WILL need to be a journeyman (50) in order to repair enchanted items. Once you are a journeyman , casting the fortify armorer spell , will allow you to repair it beyond 100% regardless if you mastered it or not.