ITER is set to come online in the next couple of years with a price tag of around $50,000,000,000 !!!! And it will spend 20 or so years testing various fuels.
China is building their own tokamak reactor to compete with ITER. I can't find cost figures, but presumably costs are roughly the same, considering the same size and is intended to "compliment" ITER.
These are still merely "test" reactors. They are experiments that may provide some enough data in 10-20 years such that another, even larger and more expensive test reactor may be constructed. Assuming ITER runs until 2045 and a replacement is started on in 2040. With 10 years of construction time, and 20 more years of testing, that means the next generation is set to complete testing in 2070. And hopefully the results of that generation will give us an idea of how to build a commercially viable fusion reactor.
All the funding in the world isn't going to change the fact that testing is a long-drawn out process, and that it must be performed in a somewhat linear fashion. The results of the previous experiments inform the next generation. And we are still a few generations away from commercial viability.
I do want to point out that I'm a strong advocate for fusion research. I just don't see it as a viable solution to global warming, regardless of how much we fund it, because we don't even know what a commercially viable reactor even looks like yet, much less be able to scale the technology out to the point that it will put a dent in CO2 emissions.