Maybe you're already doing this, but you generally want to optimize the funnels from impression -> click -> landing-page -> some conversion event. Focus on one at a time. To get better click-through rates, ensure that you have tight integration in your ad groups between the keywords and the ad copy. If you're not using keywords people are searching for in the ad, it is much less likely to be clicked. Also try dynamic keyword insertion in the ad copy if you don't feel like breaking up your ad groups. It's a bit of work, but once you find a combination that is effective, it's a matter of continuing to test new keyword permutations and dropping the stinkers to laser-target your adwords campaigns for high ROI.
It is also generally a bad idea to include price in the ad copy. You want to give enough honest information about what you're selling to make an interested user click; it is the job of your landing page/web site to build value and sell, but test to see what works for you. Hope that helps, good luck.