Depends on the laptop. I have bought two laptops in the past 14 months, a $2000 ThinkPad and a $600 Acer. Both came with 4GB soldered on and a single free SODIMM.
(On a different note: the ThinkPad maxes out at 8GB and the Acer at 12GB, whereas previous generations went up to 16GB at least. Intel intentionally nerfed Haswell and newer core i's, presumably to push their Xeons on more people)
They're supposed to be priced around $350 or so, at least that's what I see from last year. How is that too expensive? An X series ThinkPad is like $2300+ with a good config. Adding another few hundred so I can have a decent amount of RAM sounds like a no-brainer.
(Or, Lenovo could put IBM engineering in charge and figure out how to get 2 slots back on the X series.)
Be careful... the 5th gen Intel CPUs can NOT run with standard 16GB modules. There is a technical issue which causes instabilities with 16GB modules, except if the modules are specially made to cover this issue. The Intelligent Memory modules do that.
(On a different note: the ThinkPad maxes out at 8GB and the Acer at 12GB, whereas previous generations went up to 16GB at least. Intel intentionally nerfed Haswell and newer core i's, presumably to push their Xeons on more people)