Still the same questions:
1. How to become free as one of the dunmer Houses?
2. How to hire Dark Brotherhood or Morag Tong? Option "Assasinate" creates an event with only option "I've changed my mind"
1 - If by free you mean not paying tribute to the Tribunal Temple, when the current Archcanon dies you will have the option to keep paying it or renouncing it, meaning you won't have to pay any more money to them but you'll also be on your own, and the rest of the houses will have the Temple on their side if you decide to go to war against them. You can hire the Morag Tong to speed things up if the Archcanon is taking too long to die, you know...
2 -...speaking of which, the reason for that is you don't have enough money. Money for hiring the Morag Tong is dependent on the relative importance of the target. Courtiers are the cheapest, king and emperor tier character are the most expensive. The minimum is 300 gold for a courtier, but I recall killing an Archcanon and having to pay 1000 gold (maybe it was less, but it certainly felt as being
really expensive). So, save up some money for political assassinations!