Vivian took some great photos which I think was more the product of her time period (nostalgic for us now) and her quiet nature-- than any genius. Her best are in the galleries, her others look mediocre just like anyone's.
The cameras were expensive before her introduction, I know because that was when I was shopping and decided on the Yashica's. New Yashica or junk Rollei, hundred/s or thousand/s, hm... I think I'll just see if I really like this-- first. Yashica has not let me down. Have a full 35 GSN kit too which I love. My last Yashica, the 635, was bought post Maier-- it's price wasn't affected either. I could have bought cheaper in fact but I like pretty things, so don't buy beaters.
Rollei prices have nothing to do with Vivian Maier though may influence someone that idolizes her work and wants to imitate her by encouraging them to dump a lot of money on a camera so they can have instant talent-- and that perception can be associated with any camera that an admired talent uses. And I am not at all saying anything bad about the Rollei's quality, it was a fine instrument for its time (and maybe all time since they don't make TLR's anymore)
However.. It's not the camera even if a good tool is essential to the craft. If it was, we could all buy what the pros/artists have and put them out of business.
There are other TLR's besides Yashica (Mamiya-with interchangeable lenses, Minolta, Zeiss, Ansco, Tower, Lubitel, Ricoh, Voightlander-they are smaller, etc.....), Eliot--so I'm not going to push the brand I have, but I will say start with something that suits your needs and if you really love shooting at waist level, can master a caterwonky view screen and enjoy carrying a brick around your neck, upgrade to the model you fancy. The metal ones are really a lot heavier and tend to clunk against your chest when you walk.