Cost to Rewire a Tonearm?

It depends on the tonearm, but $100-150 should be enough for the job.

I would say it also depends on what litz wire is used? Kondo litz wire could costs $$$$$

If you pay someone else to do it, you are also likely to be paying a premium for the wire itself.  The Audionote silver litz wire alone, for one example, may cost you more than Chakster's estimate for the whole job including labor, if the tech acquires the wire for you.  My advice is to select and purchase your own wire and present it, along with your tonearm, to whoever does the work for you. You'll probably save a bit that way.

I’m considering Zavfino tone arm wire for a re wire job on a Well Tempered arm that’s been in the closet for a few years. I don’t know if it’s true but I have a couple friend that have used it and compared it to the Audio Note wire. 

I would estimate $100-150 for the labor alone.  The cost of cable and connectors can vary all over the map.  
I replaced the Cardas wire and KLE plugs on my Analog Instruments Siggwan arm with ZavFino 1877Phono copper Litz wire.  By that time I had already replaced the KLE  Harmony plugs with KLE Absolute so I used the same Absolute plugs on the new wire.  
I thought the 1877Phono wire was a rather modest upgrade from the Cardas.  I ended up replacing it with a Discovery cable that was even better.  It’s been too long for me to recall the details but I remember especially liking the dynamics with Discovery.

With the Discovery I followed Joe Dephillips’ advice not to use a continuous run of his tonearm wire but rather have the tonearm wires hand off to his Plus 4 interconnect a few inches out of the arm.  I also used his recommended locking RCA plugs.