That's right, for example BigShrimpin ran this site for years for less than $10 a month...the domain name alone is under $20, so unless you have a huge site with really dynamic content and thousands of hits per day it won't cost much at all. Now on the other hand look at Craigslist. They have 20 - 30 employees. One wouldn't think a site as simple as craigslist which is policed by the online community would require such a large development staff. But I can tell you they probably have a freakin buttload of servers running that site because of all of the traffic.
I've been running a crappy little site for the past 10 years.
www.copperlighting.com
I spent ~$50 for the name (it was more expensive back then) and ~$20 per month. Oh and I spent a whopping $20 on advertising to get listed in the search engines. I've had sales in over half of the lower 48!! And I don't even accept credit cards for cryin out loud!!
Ok, there's my plug for my side business LOL. The enforcer is gonna boot me for illegal advertising now.... :)