| 0 | < | Unit cost | << | Software development cost | 
|    | 
    ||||
| 0 | < | Acquisition cost of a libre software | << | Acquisition cost of a commercial software | 
|    | 
    ||||
| 0 | < | Formation cost for a free software | < | Formation cost for a commercial software | 
|    | 
    ||||
| 0 | < | Installation cost for a free system | < | Installation cost for a commercial system | 
|    |