A mistake that people often make, especially when they first enter the world of PPC, is to get involved in a bidding war over a certain keyword. Keep in mind that since PPC involves your budget, you sometimes will find it more advantageous to switch from your preferred keyword (as much as it may work for you in the SEO field) to cheaper keyword(s), especially if you are bidding against a company much larger than yours.
You must keep in mind that because you are spending advertising dollars on your PPC campaign, and not relying on robot indexing for ranking, you need to keep your bottom line always on the top of your thoughts. If you bid too high in order to get that top ranking and don’t get more sales from that higher bid than your previous bid, you are wasting advertising dollars and reducing your ROI.
Look into less popular keywords instead and spread your marketing dollars among them. It is entirely possible that by spreading your money over many keywords rather than concentrating on one or two that you are particularly fond of, you may increase your ROI by attracting the same number of visitors at an overall lower cost.
For example, if the keyword you want is currently at $10, while related keywords run an average of 50 cents each, think of how many more keywords you can add to your PPC campaign for the price of the one keyword at $10, and you will probably attract just as many visitors because of the broader reach of your choice of words visitors may search by.