It's free to join and affiliates get paid for leads and sales.
Keyword research tool provider WordStream is launching a new affiliate marketing program. It's free to join and rewards sales of the company's software products including the HYPERLINK suite of custom PPC and SEO tools.
Affiliates will get $5 per lead for WordStream Keyword Management for PPC Software free trial signups and up to $300 commission on sales of WordStream Keyword Management for SEO software subscriptions.
WordStream will provide affiliates with marketing collateral including links, banner ads, emaily copy, brochures, case studies and landing pages. Referrals on all leads and sales are tracked for 90 days.
Source : http://blog.searchenginewatch.com/100216-080043