You can use Google's keyword tool if your Google Ads account spent some money, or you can use SEMrush.
The CPC is not accurate in any of them because the CPC these days is a result of your competitors' conversion rate and CPA bid.
Even a few years ago the CPC was in opposite correlation to your QS and your actual CPC had little to no connection to the one showed in tools.
The only use for this estimation is to try and understand the cost relatively to other keywords in the same niche, and even this is questionable.