im buy a host . i just want to know how much traffic visits can support in one day with this parameters 1 Core 1 GB RAM 20 GB SSD Storage 2 TB/month transfer powered
The main limitations are your small amount of RAM and only one core. For something like Wordpress, you should be going for at least 2 cores and certainly not less than 2 GB of RAM, preferably 3 - 4 GB. If you are using a Wordpress caching plugin, you should be able to serve several thousand visitors a day on 1 core, 1 GB RAM (because your VPS will be serving static HTML most of the time which requires very little server resources). But if you have that much traffic, you should be making more than enough money from advertising to pay for a 2 core VPS. With only one core, your VPS will slow to a crawl when an update needs to be installed or worse when some update is compiled from source.