i is fantastic with great short important keywords like news, bank, blog, cash, forum etc. In other words, the word itself has to be a million dollar one for "i" to be valuable, probably iword.com is 1/100 of word.com
Valuer by itself is not very valuable name, let's say valuer.com would sell for $5,000 to 20,000 range, then ivaluer.com would be worth $50-200. But again if your buyer is an end user that has already made his mind and likes it, then he might pay more.