The Softhouse Unity Technologies, authors of the powerful graphics engine Unity, have a very tempting offer:
Unity Pro for $75 per month for a minimum of 12 months. The offer has a limited time and expires July 31, 2013.
 
Unity Pro is classified as a graphics engine "User-Friendly" by the very strong potential for ease of use and high-platform compatibility, eg, iOS, Android, Xbox 360, PS3 etc. ..
You can easily assemble a scene in the Editor Workspace and test it immediately with absolute fidelity in the sounds and graphics of the final game, while creating, animations incredible fluidity and editability of any character or object in the scene. 
For independent developers and studios, Unity’s democratizing ecosystem smashes the time and cost barriers to creating uniquely beautiful games. They are using Unity to build a livelihood doing what they love: creating games that hook and delight players on any platform.
 
Details of the offer:
  • A subscription runs for a minimum of 12 months and is available via the Online Store.
  • There is a limit of one subscription plan per customer account.
  • The offer ends July 31st, at 11:59 p.m. GMT.
  • A subscription to Unity Pro costs $75/month. Each Pro add-on also costs $75/month. And a Team License add-on costs $20/month.
  • Everyone can subscribe. If you are already a customer, you can start a separate subscription plan alongside your perpetual license.
  • You own any content that you create with a Unity Pro subscription.
  • You are committed to paying all monthly payments in a 12 month plan.
For more Info, you see HERE