To host website on Qortal blockchain should I be more than Lvl 0 ? Or it doesn't matter ?
Level does not matter, you'll only require some QORT to register your name and you'll be all set.
Good, thank you for an answer.
And what about buy orders on trade portal ?
People still can't place order to buy at price they want. Why ?
So many new versions of the Core and UI have been released lately, but there are no positive changes on this issue.
Trade portal is a legacy platform. From what I know they wanna migrate to a more sophisticated web UI version of a decentralized marketplace. They might be waiting for finances to arrive from trading fees to fund the development of that thing. In the meanwhile processing of orders must be put on halt to ensure no one takes a bath on their trades if the underlying mechanism that matches your orders suddenly goes on a funk.