Do you want a simple ReactJS freelancer, or a React/Redux freelancer? Webpack costs extra.

But seriously, the 'price-range' of a freelancing javascript developer that is acquainted with modern frameworks like React, is the full range that any freelancer, in any business can have.

Probably the very low (<10$/hour) and very high (200$+/hour) ends of the spectrum don't happen very often in this job, but still if I tell you 10$/hour to 150$/hour what would that mean?

Also it depends highly on the nature of the task. Short term will usually command higher price than long-term.