Is that a 9-5 shift or 24h? That's either $375/h which is amazing, or $125/h which is insulting.
To answer OP, depends on your location. I am in the Northeast and if you put enough feelers out you can leverage locums companies against each other. (Basically try out different sites and shifts and stop doing the terrible ones) My best rates have been $230-245/h but at non-sustainable workloads, which is doable for like a weekend or two if you desperately need the money or want to scoop a stock market dip or something.
There are also night shifts that pay like $145/h but you are basically a glorified sleep study participant. If I was younger and didn't have a family I'd live at that hospital and just get paid to sleep as my main gig, lol.
I get postings anywhere from $165/hr to $300/hr (outpt telehealth gig in NY). Most are somewhere between $175/hr to $200/hr, though above that isn't uncommon either. No idea about negotiating or landing these positions as I never really pursued them.