1.) Would the Single Core VPS for $30.00 a month be good enough to run this server with ease, have no hiccups or lag or choke, and run smooth even with plugins added onto it?
This depends on what you're running, since the performance of plugins can vary widely. I would expect the base game to run well on a single-core VDS, though, if you just run a single server.
2.) About how many slots can the single core VPS handle without any problems?
A single server would likely run well, of any size. If you wish to run multiple servers, they'd need to be smaller and you will need to optimize well. I recommend a 2+ core VDS for multiple servers.
3.) Would i run out of bandwith or ram?
You can always purchase more of either of these later, after you see how the server runs. I would not expect for you to hit your bandwidth allotment with a single server. The RAM usage depends on your plugin load.
4.) What is done and how well and strong is the server to withstand from DDoS attacks? I know nothing can stop all DDoS attacks, because some are just too strong. But please inform me on what can be done and what is done on your VPS's to help stop DDoS attacks.
We discuss how we handle (D)DoS attacks here: viewtopic.php?f=25&t=4931
. We do not specialize in (D)DoS mitigation, but our customers have told us that our abilities far exceed those of other GSPs.
5.) Which operating system should i use? My friend said windows, but which one?
You may want to consider a version Linux (such as Debian) if you are purchasing a single-core VDS, as the OS will use less RAM, and RAM will be at a premium for you. In terms of other factors, either Linux or Windows should work well.
Lastly, i have been told that a Source game like CS:S takes up 1 core, and that is it. Is this true? If so, can the $30.00 VPS really handle 1-3 gameservers?
It really does vary, which is why we give a range. We've heard of customers running a dozen Halo servers on a single-core VDS before hitting resource limits, for instance, and other customers run a single TF2 server and hit those limits. It would be best to test this for yourself and upgrade the package later if need be (we make upgrading painless).
Also.. my friend that runs a VPS through you guys said that the Windows Operation System take about 1gb of RAM. Is this true? If so, that leaves me no RAM for my gameserver?
Windows uses about 300 megabytes of RAM.
For a single server, you might also consider our standard shared hosting. We offer the guaranteed highest performance on this and you would not need to worry about CPU or RAM; we also handle game updates, backups, and so on for you, and have a control panel with a nice rcon tool and other features.
Also, what location should I host my VPS at if i decide to go with NFO? I was thinking Chicago. But is that not the best choice?
Generally the location closest to you is best. If your players are spread out across the US, consider Chicago or Dallas.