Unless Behemoth Hide suddenly shoots up in price, These are going to be cheap. Umbril Ooze is already down to ~200k on some servers with 30-40+ Or more constantly in stock.
These belts will cost about 50k~100k to make in the very near future, and they're only a level 99 Synth, Making T1 obtainable. (Easily is debatable i suppose, since getting to 110 can be a pain in the D lol).
Its going to boil down to Umbril prices, but those will probably fall pretty quick... 100k Doesn't seem crazy for this belt, though it is on the high end, and the HQ probably going to settle around 1mil(maybe lower) despite how common it will be since its got crazy good stats.
Thats my guesses, Its all going to bank on Umbril Ooze, which is actually rather common.