CS-bg.info

So i want to boost my server but i have no idea which one should i buy
what CSVP means etc...

On the question "which one" - if you seek most effective solution, then all of them combined would be best.

First there's the "regular" boost marked with a lightning icon. It places a server always on top of non-boosted servers (which are listed in random order that changes every 24 hours). Regular boosted servers are also shown on the right sidebar of the site (last 6).

Then there's the VIP boost (CSVP) - it places a server on top of regular boosted ones and are sorted by expiration date. Servers paid for longest period are on top in the catalog and the right sidebar ("Top 4").

There are also Boost packs available, which consist of, for example, 120 automatically daily-activated regular boosts, that also come at a discounted price when compared to buying the same amount of boosts one by one.

is it good for zombie mod? i have a zombie plague and I would like to hear your thoughts about my server if its okay?

It should be okay, although most of the popular servers tend to be Dust2 or Respawn/DM nowadays in my opinion.

and what is the CSTOP boost?

It's "renting" a position (1 of 4 in total) right below the site's header where you can put your server on display. At the moment all are taken and I don't know when one's gonna be available exactly.