Recently watched a YouTube video where Vocal Rider plugin ($300) from WAVES was used, it seemed pretty neat and a big timesaver.
Is there any low priced quality alternative to this plugin? Can't afford to pay $300 for this.

I think it's kind of a unique product, but they go on sale all the time, just wait for a good offer. Going through a 3rd party site like Wavesuniverse, Audiodeluxe, or Plugindiscounts can also shave off a bit. And you don't pay VAT if you're in Europe.

There is a thread about this in the Software section. I believe they mentioned Melda having MGain.

Try AutoGain Pro by HoRNet plugins

I just use Sonar's DSP function to normalize or change gain on vocal phrases. Works like a champ. I've bound normalize to a keyboard shortcut, Once the level is uniform, then I can apply automation for large changes.

I own the Waves Vocal rider and I was a very enthusiastic buyer but I found that if I really cared about how a vocal sat in a mix, I got in there and got my hands dirty and really worked the vocal track envelopes until all the important bits were heard like they should be.  Time saving won't always get you what you want.  I even found myself fighting Vocal Rider at later stages when I came back to touch up a final pass and I overlooked that V Rider was present.

I think there may be some misconception as to how to use it. Craig, it's nothing like normalizing at all, or even really gain changing on whole phrases. It can work as an automatic "compressor" of sorts (quite well actually) but the main thing for me is when you let it write its automation. This will give you a volume envelope as if you had automated te entire track yourself, that you can then edit. It basically does most of the work for you and lets you easily adapt small bits that don't come out the way you think they should. In addition, this leaves your actual volume fader free to set the level of vocals in your mix, without having to edit the envelope every time. It's really a great plugin and a huge time saver for me.

Sanderxpander
I think there may be some misconception as to how to use it. Craig, it's nothing like normalizing at all, or even really gain changing on whole phrases. It can work as an automatic "compressor" of sorts (quite well actually) but the main thing for me is when you let it write its automation. This will give you a volume envelope as if you had automated te entire track yourself, that you can then edit. It basically does most of the work for you and lets you easily adapt small bits that don't come out the way you think they should. In addition, this leaves your actual volume fader free to set the level of vocals in your mix, without having to edit the envelope every time. It's really a great plugin and a huge time saver for me.

I've used and actually own Vocal Rider, so I'm familiar with it. The main reason I don't use it is because I don't really need to ride my vocals, I just need to touch them up in a few places and as Mod Bod suggests, doing it manually ultimately gives more control. Part of this is because I may want to emphasize certain phrases due to other tracks playing at the same time, and a tool like Vocal Rider can't make those kinds of judgement calls.
 
However personal preference also enters into this. I generally don't use automation to make "fixes" but prefer to embed those changes in the file itself. I then use automation more like a conductor to change overall dynamics and also, to play the faders like a performance. 

Alternatives to Vocal Rider (only ones that I have tried):
 
TB-ProAudio's GainRider ($75)
 
HorNet's AutoGain Pro ($28)
 
Meldaproduction's MAutoVolume ($64, likely to be on sale again for $32)
 
All of these do what they claim to do. However, IMO, these are not the global solutions you might expect based on product descriptions alone.
 
They'd be useful for spoken voice editing such as podcasts made with handheld recorders. They work great for choral oohs and aahs. But beyond that, for lead vocals I've decided they're all more trouble than they're worth, and that I can get better results with conventional volume automation.
 
 
 
 
 
 

I use waves vocal rider on just about every project with no problems.