Ambience is a reverb VST plugin, many users compare it to the likes of professional studio grade compressors yet it is totally FREE! Developed by Smartelectronix, it is incredibly powerful and will suit all basic needs as well as more advanced uses.
It has the basic reverb controls found on all good units/plugins such as Decay time, Damping and Dry/Wet controls as well as many more.
What I like about Dry/Wet controls is that you don't need to have a reverb send on a different track, unless you want to do further processing without compromising the dry signal.
The sound on this goes from very subtle room reverbs to what I could only assume is impossible reverbs, imagine a huge cave that has then been sound treated to further reflect sounds.
The EQ and Damping sections are awesome, while only controlling high and low, they allow the main frequency of alteration to be selected and are important if you don't want the reverb to "muddy" up the low end.
The shape section is great, I tend to focus on the pre-delay, controlling the size of room and time between sound and reverb reflection. Having a width control greatly enhances the stereo image of the sound (another reason to roll off and dampen the low ends).
With a VST like this, there is no reason to pay for one unless you know you can make it sound better however, this will suit certainly all beginner needs at least.
The download link for it is HERE.