Phone system for tracking marketing campaings

[Michael Halow]

Does anyone know of a phone system that allows a lot of tracking numbers that doesn't charge a fortune? I am currently using call rail which I like but I only get 10 tracking numbers, and they charge a lot for more. I am looking for something that doesn't restrict the amount of numbers, or charges very little for them. For my direct mail I am mailing 7 pieces per list. I would like to put a different number on each piece so I can determine how many mailings I need before I get a call. with all the marketing I am doing I need at least 60 numbers at any given time. The phone system doesn't have to be able to track them, I use podio which will track all my campaign stats. I just need a bunch of numbers. Appreciate the advice!