Now this was 1994, so way prior to Logan join the Avengers, so no stipend there.
And while this certainly implies that the X-Men don't get any stipend, surely the cost of uniforms and such is covered by the Xavier fortune.
But what about all of the cigars he smokes, and beer he consumes? What about the cash poker games he plays? What about the personal travel to Japan or other exotic locales? Did all of that come from Xavier? Really? All of the vehicles he uses?
I think this calls for an IRS audit...
From The Bullpen Bulletins page in Captain America #423 (1994)