Ever wonder why YOU have to pay GLADIATORS to join YOUR school? Isn't that a little backwards? If only life were that easy.
Here is a way to turn that around.

You will need enough money to recruit one gladiator. After that it pays for itself.

Recruit a gladiator that uses heavy armor, like a SAMNITE or a CENTURIAN.
Take all of his gear. The way you do this is by going to the item screen, and selecting *NONE* for the gear. This cannot be done with weapons, so buy a cheap weapon to use as the replacement if you so desire.

Now sell his gear. Expel him too... he's pretty worthless.

That being said, only use this dirty trick with gladiators that you KNOW you are not going to recruit to have on your team permanently.
The reason for this is that the gladiators that you expel from your school will go back into the recruit pool, able to be recruited again.

I made 250,000 in about 20 minutes. Not a bad deal.