I LOVE TSPP, but I don't think it meets your criteria. It's far too hard for newbies to grasp. Starting MB -- other than an Itchy and Scratchy lucky shot -- is a challenge for most newbs. The game is pure awesome, but I wouldn't recommend it based on the fact you want casual players to enjoy it.
One thing I have observed over the years is a great game has an easy MB for the casual player, but depth and challenge for the more skilled player. MB, MM, AFM, ToM, etc. all have this characteristic.
I'd suggest Spiderman, JP, or Theatre of Magic.
Spidy is my fav of the three. Great game. Challenging, deep, lots to do and will keep you entertained. A very easy MB you can easily explain to guests -- first Doc Oc award. They can smash on Sandman and feel they are accomplishing something as well. Throw a shaker in there and it's heaven.
JP is a blast and has a gimmie MB. On the third ball, you can simply press the smart missile and get MB. The more experienced player will use it to get big awards and select the right time to use it. It's got a good mix of rules and a fantastic gimmick -- the T-Rex. The pinball eating dinosaur was a hit among my kids and their friends. That combined with the gimmie MB ensured there was always a line up for it when my kids had a party. True story: one little guy was standing in front of another game and asked what button he had to press to get MB. When I said only JP did that, he went back to the line up for JP! LOL! All that said, I found the game got old after awhile and sold it. My kids missed that one the most, and that speak volumes.
ToM is a fun game, but eventually gets pretty easy. That said, it was my most popular game among adults when I had it especially among the ladies. And everyone loves the MB. The ball lifting off the playfield and onto the trunk is a neat effect. Really easy to explain MB to even the most casual player. Very disappointing wizard mode, though. I haven't followed the prices on this one as I don't miss it one bit. It might be slightly outside your max price point.
IJ is another one to consider. Great family theme. MB is pretty easy to start. Lots of modes for you and more experienced players. Only draw back is unbalanced rules. Modes really aren't worth anything. Instead you focus only on MB to get a good score. Once I realized that, it killed the game for me. Still, it was a hit when I had it.
Cheers,
Duane