Depends.
Depends on what you want, and how much you play. $25 per hand X how many hours? How many hours and how fast does your wife play the slots?
Ask around the various casinos. Call the 800 numbers, ask for a casino host, and explain what you play, how much, how long, and what you want. You won't get any promises, but you will get a "feel" for how bad they want your action.
One bad thing, Everybody goes to Vegas for the Superbowl. The place is full and it is packed with hi-rollers. If you go to Vegas between Xmas and New Year's -- the casinos are begging for business and more likely to comp more. It is all Supply and Demand.
Speaking of Demand, if the casinos feel this is your once-in-a-lifetime go to Vegas for the Superbowl trip, then they probably won't comp much at all. What would be the point, you probably aren't coming back anyways.
Generally,
At the big strip properties you won't get much more than lunch.
Small strip properties a little more.
Downtown, (except Golden Nugget) even more.
Orleans is also generous.
Boulder Hiway, Castaways, and other local places even more.
At the Western, you will be treated like a God. (Unfortunately, all the Western natives can offer their Gods are rocks and a bundle of sticks).