Free Tools
PPC ROI Calculator from Bplans.com. A calculator for understanding how conversion rate can affect ROI.
Internet Supervision - Free and paid service for ensuring that you don't waste ppc money when your site is down.
AdWords Wrapper is a free time saving tool that wraps keyword phrases in "quotation marks" (phrase match) and [square brackets] (exact match) for use in Google AdWords campaigns.
Link Popularity Checker - Instant, online reports of a site's link popularity rating in 4 top search engines, including Google, Yahoo! Search, MSN, and Teoma (Ask Jeeves).
Search Engine Rankings - Instant, online reports of web site rankings in 7 top search engines, including Google, Yahoo! Search, MSN, AOL, Teoma (Ask Jeeves), AltaVista, AllTheWeb, and the top 3 web directories; Yahoo! Directory, Open Directory (Dmoz), and LookSmart.
A long list of Google tools - For work with Google campaigns.
Overture Bid Tool - Dig for relavant Yahoo terms and search phrases.
GoogSpy - Adwords competitor research; find out who's bidding up your search terms, and for which phrases.
SNAP Keyword Research - Idealab's tool for pulling keyword info from Looksmart.
Wordtracker Trial - Pull and compile additional keywords from Dogpile and Metcrawler.
AdGooroo Free Trial - Compare your Adwords keywords with the competition. This tool can help with determining whether your Adwords keyword bid is too high or too low.