Just make sure you measure your results - test the heck out of your ads, keywords, and landing pages. The value of PPC is there for those who stay on top of it.
IMO,
start with YSM (overture.com) they still imo provide a higher ROI on your keywords, create additional landing pages specific to sell your product.. ppc does take investment ..my suggestion is learn seo and build links.. natural results are by far the best way to go and will help you learn from log reports where your traffic is comng from and from what keywords.. this will also help you in creating your PPC accounts