I mentioned Construction and Prayer because they are uber fast. If you have the money to buy Construction, Prayer or Herblore or whatever skills are uber fast, then they are the easiest. It's just the part about making money. As I mentioned in my last post about the party room.. Easy money. But picking up the runes in the respawn spot in the wilderness is like 2k an hour. The party room could be anything.. Pop a balloon and get 100m. There you go, 100m just like that. The fact is is that there are different ways of making money, making the skills you choose to spend the money could be easy or hard, depending on how you made the money in the first place.