Its kinda the easy answer but I would suggest each one of you buy the new commander decks that are coming out.
A. They are 25-30 each so that falls well within your budget per player
B. Being that they are all precontructed, they are all somewhat nerfed in power level so no one is going to be heads and shoulders stronger than the other 2.
C. They are the best way to get started in both learning EDH and getting a deck started. Once you learn how each deck plays it makes it easier to see what you can look to add and trade for.
If your looking for deck ideas feel free to check my profile. Something I try to do with all my decks (I usually have about 12 built at time) is to make sure no one deck runs the same "staples" as another. Some staples you just have to run in certain colors, ie Path to exile & Cultivate, but its makes things a little more changing to not always run the best cards. It makes things more fun and tones down your deck.