Pricing break down of the project I did:
- Order VPS, order SIP lines, manage number port: $100
- Install + Configure PBX in a Flash: $200
- Setup QoS router at each site: $100*2 = $200
~$500 installation fee (PBX in a flash is free).
- 6x VOIP phones @ $150: $900
Becarra's point is valid but most Asterisk systems these days use FreePBX GUI which is quite easy to use. Maybe outsource the management to avoid key man risk issue.