Need One Keywords Avg Search Volume

[Joel]

Which service would I use to pull the average search volume for 1
keyword? I'm using the Variations service and it's returning too many
values. It's just a waste of units for me. And examples would help
greatly.

[AdWords API Advisor]

Hi,

The v13 KeywordToolService.getKeywordVariations has a fixed cost of 20
units per request, so the number of results returned will not affect
the cost: http://code.google.com/apis/adwords/docs/developer/adwords_api_ratesheet.html

However, the new v2009 TargetingIdeaService does allow for the
limiting of results, and the cost if 1 unit per result. An
introduction to this service can be found on the AdWords API blog:
http://adwordsapi.blogspot.com/2009/11/discover-v2009-getting-ideas-with.html

Best,
- Eric Koleda, AdWords API Team