Use best judgment dependent on location. In core regions, cost would be less than in outer regions.
Full body armor today weighs about 15 to 20kg. I would use that as a start. I would say that an armor vac suit at TL18 would weigh at least 70kg. At most, I would not drop weight below 60kg.
For cost, armoring something can raise its price by up +100% (perhaps even more) of original cost. Thus, I would say that an armor vac suit would cost at least 12.5K (+25%).
But that is my humble and honest opinion.
rmfr