2 gallons of Zerex G05 with shipping from Zoro Tools is $35.38
You would also need 2 or 3 additional gallons of distilled water from any local grocery store at about $1.25 each.
I'd say they are making $120 labor on this, as it only takes about an hour to do it.

You decide.
( I went ahead and replaced my thermostat at the same time, Rob has those for $39.95 :
Thermostat
)

Antifreeze by ZEREX - Automotive Fluids by Zoro Tools Industrial Supplies

BRING IT ALL BY AND I'LL DO IT FOR $100 LABOR