Before calling your prospect, it is important that you gather all the relevant information related to website visitors as they are the most ideal prospect. Service providers like LeadMagic ( leadmagic.io ) enable you to get complete information about your website visitors like the pages they had a look at and the duration spent on your website so that you can send the right message to the right prospect.
Depends on the country you're in - I've used Ringcentral in the past and it's a super easy to use VOIP system that is reasonably priced. I was able to make calls from my computer, the mobile app, and I could hand-off the call to other people on my team if I needed them to take over.