not sure if domain name is that important, for such tiny sites. Most of your traffic is going to be from search engines, so I guess you'll need to worry more about SEO than coming up with a memorable name (as people aren't going to remember it). From SEO point of view, keyword rich domain names are important, not sure how much though.
I guess there is definitely some money to be made, if the site is useful ("tool" based). Some examples:
http://selfmademinds.com/200811/mini-site-case-study-update/
http://www.calendarsquick.com/printables/index.html (don't know how much this site makes, I'd assume more than $1 per day)