The level of competition for keyword options can substantially increase your costs.
Depending on the number of people bidding on it, the special lead competition level for a particular keyword is classified as low, medium, or high.
High-competition keywords cost more per average bid, and using them can make it more difficult and expensive for your ad to earn a top-tier display position.
Using the AdWords Keyword Tool can help you find highly effective keywords that fit your budget by showing you what other advertisers are paying for them.
The tool's suggested bids column shows the average amount spent to rank in a top-level position for a particular keyword.
You can check which of your desired keywords are within your budget and create your campaign with them to improve your chances of being seen by potential customers.
The suggested bid function provides a good approximation of overall costs.
Google's first-page bid estimator tool, meanwhile, shows the cost of ranking on the first page of results based on keyword Quality Score and current competition.