I ordered (via aliexpress) some relatively cheap z-wave devices, after taxes and administration fee it was not that cheap anymore, but worth a try.
I ordered the following items, inclusion seems to work but none if them seem to be supported yet. The manual seems to be complete so I should be able to add them myself, given I have the correct authorisations.
Note: the price continuously changes and you might have to pay taxes as well.
cc: @chris I would like to add them, given some others threads I read, you can grant me some authorisations to the database. Thanks!