Funny that it doesn't mention the wide variety of very cheap prototyping kits from Crowd Supply -- including Fomu that fits entirely in your USB socket. FPGA kits on CS start at $15.

My disappointment with the FPGA world is how stuck it is in the "emulate an ASIC" rut. These things, physically, could change their whole logic and connectivity design on the fly according to instantaneous requirements, but everybody assumes you have to load them up once at reset and leave them that way. Each switch-point setting is just a flip-flop, no different from any of the ones in the LUTs.

Manufacturers enforce this treatment by providing only serial access to the switch-point settings in their tooling, but there is probably a lot of room for more flexibility, at least in some.