To include or not to include "cheap" in a domain name...?

I've got a question to all you SEO experts out there.

"To include or not to include "cheap" in a domain name...?"

Basically, I've got two different keywords. Keyword A gets approx. 10K searches, Keyword B gets approx. 15K searches. Both keywords have domains available for them. My problem is not which one to buy as I can get both of them, but which one to promote? Keyword B (the one with the more searches) starts with the word "cheap" whereas Keyword A is exactly the same, except for the fact that it does not start or contain the word "cheap" in it. Now I don't know which domain would work better. Of course I want to try and rank for both keywords but in my opinion Keyword A would be the better option as it's one word shorter and it looks more professional as I am using hyphens in the domain. But then again I don't know...

As you already mentioned buy both domains to protect yourself from potential competitors who might want to enter you niche at a later point.

As for the other stuff, i would go for cheap-watheverDOTcom. Not only does this version get more searches, but your still going to rank great for "whatever". If you only register whateverDOTcom you might not rank so great for "cheap whatever".

my 2 cents (not a professional) is that cheap should be behind the main keyword as otherwise you lose some ranking-power. But that's just what I learned here^^

Another path you could go is get the domain without "cheap", then set up a page with the word "cheap" in it (eg http://www.webhosting.com/cheapwebhosting.html), or a subdomain like cheap.webhosting.com. With the former, you could possibly target other keywords as well (http://www.webhosting.com/affordablewebhosting.html)

Or get both!