Google prefers hyphens instead of underscores

Straight from the Google docs:

Consider using punctuation in your URLs. The URL http://www.example.com/green-dress.html is much more useful to us than http://www.example.com/greendress.html. We recommend that you use hyphens (-) instead of underscores (_) in your URLs.

Alternatives to PPC (Pay Per Click)

Check out www.exactseek.com/featured_listings.html

They claim about 150 Million + Searches per month.

Benefits include:

- You Choose Your Keywords (you have to check availability with their tool)

- They cap the limit of keywords that can be bought

- No Bidding 

- No PPC

- No Click Fraud 

- Quick Inclusion (between 6 to 8 hours)

- World Wide Placement

- and some stats tracking is available.

Best of all is the low cost pricing:

$3 - $4 per Month