Can't afford a Rolleiflex? Here are some alternative Twin Lens Reflex cameras to consider
First, a couple things to bear in mind; the condition of the taking lens and the integrity of the camera body are of paramount concern--anything else can be repaired or replaced, but if the lens is degraded by fungus, separation, or significant damage, or if the camera has been dropped or jarred severely enough to misalign the film plane, image quality will suffer. On the other hand, minor to moderate wear, even visible fine scratches to the lens, while off-putting to owners who care more about camera cosmetics than performance, will have a negligible effect on the images produced. As long as all parts are present, and the lens/body are aligned, nearly any TLR with a four-element lens can produce outstanding photographs.
A note about lenses: nearly all of the cameras I will mention have a four-element lens modeled on the Zeiss Tessar. They are well-corrected, light-weight, and under most shooting conditions produce images indistinguishable from those made by far more expensive five- and six- element lenses in later Rolleiflex models (and a handful of other exotic TLRs). You might say that the Tessar type is the gold standard of TLR lenses.
So, in order of preference, here are the cameras I would recommend starting with before sinking hundreds (or more) into a Rolleiflex.
Ricoh Diacord (Model G, L, or Ricohmatic 225) These TLRs have, for my money, the best combination of tack-sharp lens (Rikenon 80mm f3.5), intuitive dual-lever thumb focusing, reliable shutter, ease of use and service, and build quality. The controls are laid out so that the user can hold the camera, adjust f-stop, speed, focus, charge the shutter, and fire without ever removing their hands from the camera.
Minolta Autocord (preferably with an earlier unmetered model) This is a close second in my book, and many users rate it higher). The Rokkor 75mm f3.5 taking lens is one of the best Tessar clones ever made, the top-to-bottom crank-wind film transport eliminates film flatness issues, and the bottom-lever focus mechanism is nearly as intuitive as the Ricoh. The Autocord gets a slight downgrade for the fragility of the focus lever (they are frequently bent or broken), and for the fact that it is difficult to find one that has not been heavily used (a sign of their popularity with people who actually use their cameras for more than decoration).
Yashica Mat (avoid later 124G models). If the Diacord and Autocord are the Lexus and Acura of the TLR world, the Yashica Mats are the Honda or Toyota. Yashica produced the -Mat, -Mat 124, and -Mat 124G (G for gold meter contacts) for over two decades. They feature a crisp Yashinon 75 or 80mm f3.5 lens, crank wind, and relatively low prices due to their ubiquity. They use knob-focus instead of a helical lever, so they are a little less ergonomic than the two listed above, and I would rate them slightly lower (but still very good) in the reliability department.
Rolleicord (III or IV models preferred) Franke & Heideke produced the Rolleicord from the 1930s to the 1970s as an entry-level model in the Rollei line. They had knob wind instead of a crank, levers for adjusting aperture and shutter instead of knobs, and a Schneider-Kreuznach Xenar 75mm f3.5 lens (which I actually prefer to the Zeiss Tessar). I think the model III and IV had the best combination of robust components and ease of use. I avoid the model V, Va, Vb, and Vb II cameras, since they usually fetch higher prices without any increase in image quality or usability (and I prefer a round vs. pentagonal aperture).
Zeiss Ikoflex (models with Tessar, Compur-Rapid shutter, and from a dry climate). I hesitate to list these, since I've had a couple of stinkers sold to me under the "looks great to me" auction description, Zeiss also never achieved the combination of build quality and ease of use of their competitors. However if you can find a well-cared for model (that has not been exposed to humidity--a weakness of Zeiss cameras in general) the Tessar lens will give excellent results. Unless you can actually hold one of these in your hands and examine its function,
Meopta Flexaret (VI or VII, with Belar lens and Prontor SVS shutter) Well-made Czech TLR, with lever focus. Good image quality, but build quality and availability of parts are what can be expected from Eastern Bloc manufacturers. .
The Rest. There are literally hundreds of models of TLR from dozens of manufacturers, varying in quality from crap to excellent. I have had good experiences with cameras from Voigtlander (Brillant or Superb models, quirky but sharp); Olympus (rare and expensive, but excellent lenses), Konica (Koniflex was very advanced for its time, superb lens, but hard to find and pricey), SEM (well made French TLRs, some good lenses, but usually overpriced), Kowa (their Kalloflex was built like a tank, cracker-jack lens, crank wind--somewhat hard to find, but worth the money for which they usually sell). Countless others make great photos at reasonable prices, and some make sublime photos at ridiculous prices (my personal white whale is the Fujicaflex--I hope to find and shoot one before I die). There is a wealth of information online regarding some of these lesser-known cameras and manufacturers, some of it reliable, but most of it conjecture. I've found that to really assess a camera, I've got to shoot it.
There are a lot of subjective factors that determine the best camera for your (or your your needs. Perhaps my best advice is to buy the best-maintained camera you can get within your budget, then shoot it until it becomes second nature.