The Makerbot Thing-O-Matic
is only 1,100 dollars for a full kit. The Reprap Prusa Mendel
can be a bit cheaper, sometimes as low as 5-600 dollars fully assembled, and even cheaper if you source your own parts.
Both of these options have good 'stock' capabilities, and are cheaply modifiable for very high resolution printing (mostly software/configuration tweaks).
The print material for both is inexpensive ABS filament which costs about 40-50 dollars per Kg. In my experience, a typical gaming miniature should cost no more than a dollar in material and thirty to forty-five minutes of machine time.
However, these machines aren't really capable of 'supported' printing (where soluble support material is used to allow for complex shapes and over-hangs to be printed) without extensive modification. You could do something like the tank in the first image easily, but the vanship and Typhon prints would need to be printed in parts and assembled.
There are a few 'hobbyist' grade machines capable of multi-material printing, such as the Makerbot Replicator
(1,800 dollars or so). These make printing with support material much easier (though currently this still a new technique for these machines, so it's not fully supported in the software. I expect that in a few months it won't be a problem). It's a bit more expensive and time consuming (water soluble PVA support material is about twice as expensive as ABS) but still considerably easier and cheaper than using nylon or some hideously expensive resin techniques (I don't think nylon is that much more expensive than ABS, but it take longer to print with and is a bit more finicky. Resin is generally very easy to print with, but is like a minimum of 100x as expensive as ABS and isn't nearly as tough as either Nylon or ABS).