So it depends in how many individual drives you want it, I am from NL so that's where I draw reference from.
The lowest $/TB I have seen have been on 18TB drives new(HC550's) which had an insane deal for 200 euros a piece(For new drives with warranty etc this is basically an insane deal), which means it's 11.1 Euro/TB so the cheapest way to do that assuming you do raid0(so 0 redudancy if 1 drive fails you lose everything) it would be 9 of these drives(162TB).
So assuming you don't want 0 redudancy I would say on an array of 9 drives you would do(depending on what your focus is on you would alter how many vdevs etc) 2 drives of parity(raidz2 assuming your using ZFS/RAID6 in others), which would mean it would put you to 11 drives which would at this "best price" would be 2200.
Generally the best no deal price I have seen is around 300 euro per 18TB drive,so assuming you do that deal the no redudancy array would cost you 2700, and the array with 2 drives of parity would cost you 3300.
Do realise this is dutch pricing, which might vary widely from where your from. And this is buying new and you can generally find recertified drives cheaper while not necesarrily being worse.