I feel certain that some people are going to jump all over me for making the suggestion, but if just want to wet your feet with medium format before jumping into the water, and you are something of a risk taker, you might consider a used Kiev 88CM on ebay. Older Kiev cameras such as the 88, 6C and 60 dont have a very good reputation, and rightly so, but the 88CM is a much better design and is quite a good camera in my opinion. I bought mine on ebay for $175, and the seller even paid shipping from Seattle. For that I got a camera in almost mint condition, two backs, a regular prism plus a TTL meter prism finder and a 80mm multi-coated lens. And even though the older Kiev cameras are not very reliable the line of lenses was outstanding, plus you can even use on the Kiev 88CM the superb Carl Zeiss Jena lenses made for the Pentacon 6.
This option is especially attractive should you need telephoto lenses because there are some really outstanding lenses available for the 88CM at very low prices, such as the 180mm and 300mm Sonnar lenses made by Carl Zeiss Jena. I personally have far less than $1k invested in my Kiev 88CM kit at this time and it includes, in addition to the camera and backs described above, the following: a 50mm Carl Zeiss Flektogon, a 65mm Mir, a 120mm Vega, a 180mm Sonnar, a 300mm Sonnar and a bellows.
OK, so now everyone can tell me how wrong I am!!
Sandy