Credits to Nachteule for keeping records and Destiny GL Beastmode for extracting the information out.

Most recent commander cost as of 2017-09-05, sorted alphabetically

Alfred: 2,400 1x DNA
Anatoli: 4,500 1x DNA
Armoray: 1,600 1x DNA
Azrael: 11,000 1x DNA
Brian: 39,340 1x DNA
Burglar Kate: 34,245 1x DNA
Caroline: 32,226 1x DNA
Cryptor: 1,600 1x DNA
Cynthia: 34,363 1x DNA
Dark Flagship: 12,096 1x DNA
Dor: 2,400 1x DNA
Fearsome Devil: 7,066 1x DNA
Fedor: 47,000 1x DNA
Fitzgerald: 8,750 1x DNA
Future: 44,836 1x DNA
Galaxy Lord: Unknown: Probably 90k 1x DNA
Geoffrey: 2,400 1x DNA
Herbert: 33,852 1x DNA
Incendos: 1,500 1x DNA
Ivan: 1,600 1x DNA
Jones: 2017-08-25 Unknown: Probably 50k 1x DNA
Joya: 1,500 1x DNA
Knous: 32,125 1x DNA
Krill: 3,925 1x DNA
Louise: 13,066 1x DNA
Maggie: 2,400 1x DNA
Okto: 800 1x DNA
Paccar: 1,600 1x DNA
Raksha: 12,000 1x DNA
Roxy: 800 1x DNA
Sirenne: 2,000 1x DNA
Starlord: 12,180 1x DNA
Stratus: 2,400 1x DNA
Sturdy: 17,574 1x DNA
Ursa: 11,000 1x DNA
Warden: 800 1x DNA
Zagoev: 2017-08-17 Unknown: Probably 23k 1x DNA