I've had a quick read of the Companion to the Roman Army and doubled checked. The legions did receive a stipendium for their service in the army, but a lot of expenses for equipment were taken out of it. Which is how the war in Hispania raged on as long as it did. There were slim pickings for soldiers to make extra cash on the side by looting things.

But yes, eventually the Roman armies got to a point where the Generals paid them. Or the generals negotiated with the state to get their soldiers the best deal for when they reached the end of their service. But it wasn't a guarantee of loyalty, just look at Lucullus for an example where the army dumped him to go home. Even though they were 'full of gold as used to luxury.'