I think that you might have been playing the new Hammond B3.
Organs have lots of parts, but a new instrument has millions of dollars of research and development put into it. The company has to get a pay-back for this investment. Then there is the fact that "Hammond" is the only game in town, so just like Lexus and Cadillac, they can charge for the name - the prestige of ownership. Another factor is that these big organs are typically purchased by churches and professionals who can afford (or at least come up with the money) the high price as opposed to a normal family for use in their living room. And finally, these instruments are essentially hand-made. There is no high-speed moving assembly line, so the labor costs are very high on a per-unit basis.
Also, demand has a lot to do with price. A good used B3 runs about $5,000. A really good used B3 from a "used B3 company" can run $10,000. Used organs (like Lowery, etc.) are a lot cheaper. For example I was looking at a Thomas console for $250. Nice organ, but I'm not interested.
The B3 model is the most desired, so it is the most expensive. (Actually the 1956 & 1957 years are considered the "best" years, so these instruments command an even higher price). As others have pointed out on the forum, a C3 will do the job, and you can pick up a used C3 and Leslie for about $2,500 - maybe less.
I sometimes dream about finding a person who has had a B3 in their living room since 1956 and had decided that they just want rid of the old coffin. "Just take it away, I want it out of here!" (Be still my heart!)