i have developed lots of games using unity and using expensive software such as cinema 4d... i give them all away for free but i wanted to start selling games... am i allowed to sell games using the unity free version?
Yes, the only restriction is that if you meet the following condition you must use Pro
Companies or incorporated entities that had a turnover in excess of US$100,000 in their last fiscal year must use Unity Pro.
Different software will have different publishing rules. If you're planning to release the game, make sure you have a legitimate copy of all software that you've used, and you've checked their licensing information.
As Eagle32 says, you're fine to sell games made with Unity, with the exception that once you or your company has a turnover of $100,000 or more, you need to buy a Unity Pro license.
further to this gentleman’s questions… I have a unity pro trial licence which I received with the Oculus Rift. I have released a tech demo but am considering developing further into a paid for game which I will release when the CV1 is released. I sincerely doubt I will break the $100k threshold (I can dream), but is there any problem with me releasing a paid for game with a trial license in the short term? Note - I am highly likely to start a subscription when my trial ends. Unity is fantastic.