you could use your own armorer and buy sheets of AR500 from
https://www.leecosteel.com/ar500-500f-steel-plate.html
looking at that page you might need 30 of their 96X96 inch sheets, though i might be WAY off since im operating on a lack of sleep
then you can get the Kevlar for the gambeson here
http://www.cstsales.com/aramid_fabric.html
all in all probably a tad under 3k usd not counting the hours spent making it into a suit
to add 20 10X12 pieces of AR500 steel was marked as 1700 usd on amazon, and i figure you can get further savings from more of them being ordered, the kevlar is way cheaper
https://www.amazon.com/TEMCo-Square-.../dp/B00O3KL8C2