Step 1:You have to go to final sun                                   

Step 2:Go on top were it'll say sun edit                          

Step 3:Scroll down until it says final sun version.          

Step 4:when its open fully, go to units or buildings       

Step 5:On the left it'll have a name of a unit/building. 

Step 6:Click on one, it'll say for example: Cost $975 

Step 7:You can change it to what ever you want.       remember you can change any thing house, speed,   ect...