“Cost-per-click (CPC) bidding means that you pay for each click on your ads. For CPC bidding campaigns, you set a maximum cost-per-click bid - or simply "max. CPC" - that's the highest amount that you're willing to pay for a click on your ad (unless you're setting bid adjustments, or using Enhanced CPC).” - Google
Here are 5 ways you can reduce Cost Per Click in Google Adwords:
Make sure your Adwords Ad copy is relevant and matches with all associated paid and earned media, for example, ensure landing pages, blogs, etc matches the promotional ad copy if applicable. You can check the keywords tab inside Google Adwords to display relevancy level on specific keywords, anything with a below average relevancy level indicator will need to be spruced up.
Adwords uses relevancy to measure and assign a quality score to your ads, this also establishes ad ranking, Try to include the ad group keyword within the headline and description, in short, the more relevant your ads are the better the ad ranking and better the quality score.
Longtail Keyword Strategy
Use Google Adwords included keyword tools to find as many relevant keyword variations and Longtail keywords. Longtail keywords are used by anyone trying to narrow down SERPs to a more specific level, but also using this kind of strategy has lower CPC on average as you won’t be racking up extra cost for unnecessary impressions that are more competitive by default.
Finding an equilibrium between keywords that won't host as much competition vs Longtail keywords that show up often is lower search volumes is a balancing act in itself but definitely worth it.
Click Through Rate
Pay-per-click marketing digital efforts are effective and you can see the results fast, after running analytics on your best current running ads, try to create new ads to compete against your top performing campaigns. Try to mix up your use of keywords, try introducing new calls to actions, while trying to improve customer experience every step of the way, regardless if you have a perfect quality score.
Lower Your Bids
After incorporating all of the suggestions found here you will more than be seeing you’re seeing that your quality scores going up and your ad ranks are going up as well from proactively making improvements in line with Google’s Adwords policies.
Now you can then start lowering your CPC bids in small decrements while keeping an eye on your average position and make sure it doesn’t suffer, so you should be able to keep your high ad rank and a lower CPC for those specific keywords