If you're wanting to work on a stage but are on a budget, one option is to add a little mental magic to your show. Because they focus more on the people, mental stunts tend to play big and require few if any props that often don't even need to be seen well by the audience. Just be careful routining that way and make sure any mental magic you add fits smoothly with the rest of your act.
ABSOLUTELY NOT!
Mentalism is far more demanding than Magic for starters; it requires far more showmanship to sell. Secondly, this push to put mental effects into a magic performance is hurting those that do proper mentalism. The two forms are related just as Mime is related to Magic but they are NOT one in the same thing. One invokes belief while the other suspends it; one is an agreement with the audience that you are going to be tricking them while the other is viewed by the audience as some plausible, though "fantastic" (in some instances).
Yes, when executed properly Mentalism can "Play Big" but you'd best have the chops to pull it off.
If the individual isn't yet versed in Magic then they should not attempt to move into Mentalism or even Mental Magic yet, they simply are not ready especially when they are under 20 years of age (30 is actually the best age for moving into Mentalism but we're talking pragmatically here, not how the trend has unfolded).
And Before It's Stated. . . yes there have been some brilliant young minds to come along in Mentalism but they are quite rare; a few of them being my own students or those of Kenton Knepper. Very, very few achieve public acceptance without long term guidance and coaching. This can be said about traditional Magic but not to the same degree as we find with Mentalism.