AirPairme – a platform to put in contact people that have issues with their code and devs with knowledge to solve those issues – offers a $20/hour off in their rates if you allow the recording of your session. Contribution to open source movement and user generated content for AirPairme at the same time.
Zendesk encourages to choose a more expensive plan just by emphasizing not only it visually, but also adding a ‘Try’ button that it’s not present in the rest of the plans available. A similar petithack can be found in Animoto’s site.
Betabrand knows how important can be to have as many data as possible of a potential customer. When they invite to you signup for future offers, they give you two options: either get a 10% discount in your next purchase if you just enter your email, or get a 20% OFF if you sign-up with your Facebook account instead.