Prison Architect
16 Achievements
50-60h
D.B. Cooper
Sell your prison and make over $1,000,000 profit
10.2%
How to unlock the D.B. Cooper achievement in Prison Architect - Definitive Guide
NemoG
When you go to "Report" (press 
) and select "Valuation" you can see the profit that your prison has made. You get + value for many things, examples are the buildings, your staff, prisoner Capacity and cash on hand. You get value (penalties) for deaths and escapes in the past 24 hours. Also you have a starting $1,000 which doesn't help (though this depends on your difficulty). When your value is at $1,000,000 and you sell the prison (also in this menu) the trophy will pop. You can also quick view the value of your prison by pausing the game (press 
).
CheshireMulisha
You can see your prison value from the Valuation section of the Reports menu. The value of your prison can be improved by increasing the physical size of your prison (buildings, extra land, etc.). The amount of staff you employ, prisoner capacity and number of prisoners. You'll lose value for any bank loans and escapes or deaths in the last 24 hours.
You'll need to build a reasonably big and efficient prison to increase the value and once the value gets to over $1 million you can sell it from the Valuation screen.
Selling the prison doesn't stop you from continuing to build/manage it so as soon as you have a sellable prison for $1,000,000 you should sell it.
You also won't be able to sell your prison if you have any deaths or escapes in the last 24 hours.