I got the Gigabyte GA Z170 HD3P motherboard and unfortunately i must buy only from this online store :
http://www.e-shop.gr/ypologistes-mnimes-ram-ddr4-sdram-dual-channel-2133mhz-2400mhz-list?table=PER&category=%CC%CD%C7%CC%C7+RAM&filter-10099=1&filter-207=1&filter-5738=1&filter-6653=1
Here is a link of mobo's ram official support (just click support list under supports and downloads):
http://www.gigabyte.com/products/product-page.aspx?pid=5495#
which of those are compatible ? 70 euros max
http://www.e-shop.gr/ypologistes-mnimes-ram-ddr4-sdram-dual-channel-2133mhz-2400mhz-list?table=PER&category=%CC%CD%C7%CC%C7+RAM&filter-10099=1&filter-207=1&filter-5738=1&filter-6653=1
Here is a link of mobo's ram official support (just click support list under supports and downloads):
http://www.gigabyte.com/products/product-page.aspx?pid=5495#
which of those are compatible ? 70 euros max