I'm pretty sure that I didn't use a mobile number when registering for the Fongo phone app. For FreePhoneLIne I think they ask for a number, but I also believe it is possible if you contact support via a support ticket (
https://support.fongo.com/hc/en-us/requests/new ) for help registering if you don't have a phone to use. It's changed a few times over the years, I know for sure I haven't used a mobile for the all the numbers I have with them.
There is no problems calling 1800 number. Short codes like 411 yes, but not free call numbers. 911 is the exception which works.
https://support.fongo.com/hc/en-us/arti ... be-called-This is the page of codes they offer
https://support.fongo.com/hc/en-us/articles/212436806When you register you should get a choice of a few numbers to pick from, or you should be able to keep refreshing until you get one you like. Again, it's been a while since I last registered and things may have changed. The best thing to do is run through the signup and see what you get. It's free to do so you will not lose much apart from a bit of your time.
Hope this helps.