There are plenty of reliable cheap hosts. Ive used eukhost, and uk2.net but there are a number of other "bargin" hosts out there.
The important thing (to me) is whether they offer scalable solutions. So eg this host may offer a free services shared with a 100 other sites. Thats fine becasue most people never really make the most of their site. So you could be sharing with a dozen sites that have a combined traffic of 4 visitors. No problem there then!
Its prob worth mentioning that big ol' modern servers can actually run many more sites that those of a couple of years ago - so this is one area where past experience means nothing! RAM, storage and CPU power have never been so cheap but the multi core era ensures one site cant take all of you down with it! This will only get cheaper and more powerful. Its sad to see some hosts are still selling pentium 3s with half a gig of RAM and a few gb of bandwidth for £100 a month. Whats worse is that some people still clearly think thats good value!!
Anyway, back to the point, ensure your provider offers scalable solutions and monitor your traffic closely with something fairly simple, free, yet robust such as Google Analytics.
If and when your site picks up and you see site usage affected by performance then you buy into the next hosting plan. In that way I generally start off with the mass shared host option - say £20 for a year. You can get the site up and indexed with no real risk. If your fantastic idea is a winner (and 9 times out of 10 it probably wont
!) then you just get on the phone and upgrade. Buy some more bandwidth, move onto a VPC, hey if it goes really well you can get ya own dedicated server!! But lets be honest, most part time affiliate sites are never going to need the power of a whole server!
Assuming you have a modern broadband connection you should be able to backup your site yourself to a local drive. Unless you run a media rich site you are unlikely to have any serious amount of data that cant be brought down and put up in minutes. Id suggest automating this if you havent already
.
You would be suprised what my employer's 1m+ visitors a month site is hosted on! Although ultimately it will depend how well coded your site is!
Personally I think times are changing, with better automation and bigger boxes and the new virtual era hosting will change dramtically. Low cost high volume hosts are now a reality and those that havent invested in the infrastructure will fall away.
This is good news for the consumer - although tbh in a decade or two we'll host the stuff in our living rooms so its not a business id invest in!! Roll on 100mb domestic sdsl connections
GL