toll-free-telephone-numberThe best deal I found was simple:

https://www.800.com

You can choose to have the phone ring on as many numbers as possible – for something like 6 cents/minute. Or you can choose to have it go directly to voicemail, then return the call later. You can route the voicemails to emails — so you could then pick them up anywhere in the world. Lots of flexibility — and lots of options… for the right price. (Of course, be sure the number is toll-free in the country in which you need it to be.)