if there are anything as a price (res or token) I think it's good. However, the resource should be higher or equal to the total res needed to make that OP, and the OP's upkeep will be "transfered" to the new owner, as well as 12 control tick needed. The resource the "seller" received will be smaller or equal to the amount of resource gained from downgrading and razing those OPs.
For example, I "sell" 3 radars to another alliance, that guy will need to pay at least 3000 metal, oil (don't know the exact price for oil
![Neutral :|](./images/smilies/icon_neutral.gif)
), 45 workers as well as the upkeep. I'll receive back 1500 metal and 15 workers. No matter if those OPs are built by me or taken from someone...