How could that be? It has typical stealth featuers, which means its investment in R&D would be higher, if not a lot higher. It has two engines, which means what's too obvious to discuss. It then shoud have all the rest that the J-10 has. So why did you think it would sell at the same price as the J-10 does? It can't be "cheap", it can only be relatively inexpensive or, more precisely speaking, less expensive.
P.S. It's not a light weight aircraft (that would be stuff like LCA). It is a medium weight aircraft.
I agree, this aircraft most likely will be priced "less expensive" compare to J20, but by no means cheap. Although air frame are considered cheap in China, avionics and engine will consume the bulk of the price. Speaking of engines, that's probably the biggest uncertainty of this project. We know development for the 9500kg class medium thrust engine (WS13A variant) at least started in 2009, so it probably will be another couple of years before it's ready for prime time. The prototypes most likely will fly with RD93s.