cost of using adwords api for managing ads

I'm trying to find out what using the AdWords API costs before digging into it - as I don't see the fun in blowing a budget on getting code to set up only to find it's too expensive to run.

The scenario:

• List item
• we've got a number开发者_如何学C of campaigns with a total of about 50,000 keywords
• we want to manage these keywords as automatic as possible (which essentially means getting current info about the keywords, settings status for keywords - pausing them if needed - and managing bids)

Basically, this means querying the API service for info on all adgroups, updating specific ads or keywords as needed.

Am I correct in reading the http://code.google.com/apis/adwords/docs/ratesheet.html to mean that getting info for keywords is 1 unit per keyword, meaning a minimum spend of 50,000 units to get the info? Is there an option that doesn't suck up units like there's no tomorrow?

FYI google preferred pricing is retired .. they are providing api for free with two levels of access.

Based on feedback we've heard, and to encourage continued innovation, we are making AdWords API usage free for developers, starting March 1, 2013. Adwords API preferred pricing will be retired.

Going forward, there will be two levels of API access: Basic and standard. Basic access is provided by default and allows up to 10,000 operations per day. Standard access is available to qualified developers and has no daily limit on operations. With either basic or standard access, there will be no charges for AdWords API usage.

for more info http://googleadsdeveloper.blogspot.in/2013/01/new-simplified-adwords-api-pricing.html

Got an answer from Google - http://groups.google.com/group/adwords-api/browse_thread/thread/03992636b7dc99ce/0816836f826cbd1d?lnk=raot#0816836f826cbd1d

Retrieving 50000 keywords using AdGroupCriterionService will cost you 50000 API units as per the rate sheet. Instead, you can use a keyword performance report to pull your keywords and their stats. You can create one report definition for 400 units and download the report daily; report download won't cost you any API units. Updating the status and budgets will cost you API units, but chances are that those costs are lesser since you may not update 50000 keywords every day.

So there's definitely a better way to query the data