A more recent source says this (found through wikipedia). Values all appear to be up to launch, and do not include operations.
NASA: 8,800m
ESA : 850m
CSA : 200m
------------
All : 9,850m
"Günther Hasinger, ESA director of science, estimated that Europe’s contributions to JWST, in the form of instruments and the Ariane 5 launch, to be about 700 million euros ($850 million), roughly the same as an ESA “M-class” science mission.
Gilles Leclerc, director general for space exploration at the Canadian Space Agency, said Canada’s contribution of an instrument and fine guidance sensors cost the agency about $200 million Canadian ($165 million) over 20 years. “This is an investment in discoveries of the universe,” he said.
NASA now estimates it will spend $8.8 billion on JWST through the spacecraft’s launch."[1][2]
Those numbers line up with a summary the Planetary Society put out.[3] That source includes info on the operations cost, at least for the US:
"The James Webb Space Telescope (JWST) is expected to cost NASA $9.7 billion over 24 years. Of that amount, $8.8 billion was spent on spacecraft development between 2003 and 2021; $861 million is planned to support five years of operations. Adjusted for inflation to 2020 dollars, the lifetime cost to NASA will be approximately $10.8 billion.
That is only NASA’s portion. The European Space Agency provided the Ariane 5 launch vehicle and two of the four science instruments for an estimated cost of €700 million. The Canadian Space Agency contributed sensors and scientific instrumentation, which cost approximately CA$200 million."
All three agencies will supply staff to support operations, which I guess makes sense since they've all contributed different instruments.[4]
[1] https://spacenews.com/jwst-launch-slips-to-november/
[2] https://en.wikipedia.org/wiki/James_Webb_Space_Telescope#Cos...
[3] https://www.planetary.org/articles/cost-of-the-jwst
[4] https://en.wikipedia.org/wiki/James_Webb_Space_Telescope#Par...