How can I block certain websites and services from trial users only?
the problem is, I've got 1 router serving trials users and paid users. and only want to block stuff from trial users
I'm using wifieasiest way is to separate them out, just add (I presume you are using wireless) virtual AP with different SSID and different address space where your trialists are connecting and manage their traffic completely separately from main AP.
it is, and you have to use it. Either use separate SSID, where trial/unauthorized users can connect with limited access to internet resources, or use hotspot with walled garden, where limited/unauthorized users can access only certain pages.
Either this or "creative" users might get free internet access on expense of non-trial users.
the problem is, they buy vouchers via credit card and from voucher outlets, so they will need to login with username and password, so automatic login wont work hereplease see the wiki.mikrotik.com on how this can be accomplished, of course you can implement 2 servers or even 2 separate networks. That is your choice. However, cost effective implementations are as described. I would go with this one: trial - without authorization, can only access pages you allow in the walled garden, authorized - can access everything. Also, you can create automatic MAC authorization so you single out full users while the rest of the bunch get limited treatment. Nothing changes for paid users as login is automatic for them.