Go to Ritz Camera

To get a medium format camera, you don't go to Ritz. They don't carry any - they have given way to digital, carrying only a minumum number of film cameras and no medium format.

To start, I would either go with a Pentax 645 or 67 or to Mamiay 645, RB67, or RG67. There are others, Fuji makes a few.

To ensure that you get one that works, I don't recommend ebay. I would call www.keh.com and talk to Arthur if you can get him on the line. You will...

If you can find one, a yashika mat 124G is an inexpensive way to break into the medium formats. The size is 6X6. Whatever you go to, remember that it is going to be used (new is way too expensive) so be careful.

The mamiya line up are all very good, and middle priced.

Heya,
All the advice they gave you was great but here is another option for you.
I don't know what intentions you have for a final outcome so that would help, like is it just for artistic use, weddings, commercial or whatever. If it is purely artsy may I suggest this as a fun, very cheap way of entering the medium format world, having those nice big negs that will create great results. There is a camera, (once called the Diana) but now the Holga. They can be found...