Provider to recommend to your parents or grandparents: Callcentric
Provider for hobbyists who need flexibility: voip.ms
Provider for cheapest termination rates and flexibility: Anveo Direct (not the consumer product)
Bria and Groundwire have good SIP softphones for mobile, but aren't free. Since multitasking on iOS is so limited, these apps can register on their own servers, then send push notifications on calls.
3CX or Asterisk are good choices for connecting to trunks. 3CX is much less flexible, can cost money, but is "easy".
Provider for hobbyists who need flexibility: voip.ms
Provider for cheapest termination rates and flexibility: Anveo Direct (not the consumer product)
Bria and Groundwire have good SIP softphones for mobile, but aren't free. Since multitasking on iOS is so limited, these apps can register on their own servers, then send push notifications on calls.
3CX or Asterisk are good choices for connecting to trunks. 3CX is much less flexible, can cost money, but is "easy".