What do you know of VPS deals under $20 per month?
How effective and reliable are they?
I ask as I plan to use one from MicroVPS.com.
Thanks.

I can half that http://cheapvps.co.uk/ - you can pay me the difference

Does MicroVPS.com provide their VPSs only on Linux OS? Or do they provide any other ones?
For that price they offer much HDD, RAM and bandwidth.

I have never heard about this company before. But I know reliable and trustworthy company which will meet all your specifications. Check out A2hosting.com VPS offers. If my memory doesn't fail me, the prices start at $ 14.95 per month.
What can you say about this offer?

MicroVPS.com is specializing on the high quality e-commerce, web, business and game hosting services in the United States at low cost.They offer much HDD, RAM and space for that price.
Think they are a good start for running your business successfully.

I heard micro vps provides dedicated, self-managed hosting and they are reliable.

In my opinion, this company is reliable, but comparison will give you well-marked picture what company will be better for you. Have a look at Exmasters.com as they offer also cheap VPS hosting plans on favorable terms.

Nice VPS deals you can get from Globaltap.com. All virtual servers they provide run on the state of the art hardware with plenty of CPU and memory resources.

I'd like to add that taking into account low prices on Microvps.com services, they offer a 10% discount - UAF3SV.
Hope it will be helpful for you.

I can recommend you to do a kind of research and you can also look at hostican.com, exmasters.com and hostgator.com - these companies will suit you down to the ground, compare them and choose the best one for you.