I am aware of a few people in the same boat as you, and they all have the same thing in common. And that is they keep looking for the cheapest host they can find.
I suggested that they and you look for the well know hosts that have been around awhile. Some of them are McHost.com, HostingMatters.com, Venturesonline.com. You will save money in the long run by using a quality host.
i'd like to add Voxtreme.com, Weberz.com also to the list of Sitekeeper
one free service to moniter downtime (they give email to u) is InternetSeer.com which i have used for long time. (Free monitering is limited to 5 websites and at interval of 30 mins). Netwhistle was also nice but they had stopped free service long back