phone calls with no plan

When I got my first bb - Javelin - I believe it was called, a very helpful tech support person helped me set it up to make wifi calls. I had a Roger's account (in Canada) and no data plan. I was able to shut off all connection to the service provider, and only keep wifi active, and I was able to make phone calls. When I went to the blackberry desktop and updated my OS, suddenly, I was no longer able to do this. When I called Rogers they said they do not offer support in this area (I think they said I should contact the manufacturer). I tried adjusting my settings but was no longer able to access this very cool feature. I noticed Roger's then offered wifi phone calls on top of their normal plan for an additional fee. Hard to justify this after I had it for free!

I got fed up with Rogers and their expensive services and just cancelled everything. I now have 3 blackberrys in my house hold with no plan at all. Here's my main question:

Is there a way to use a blackberry without any plan whatsoever to make wifi calls?

secondarily:

if not, are preloaded SIM cards available in Canada? and if not, are preloaded SIM cards available in U.S which will work in Canada?

I always loved my blackberrys, but hate Rogers and the other monopolistic phone companies (Bell) in this country. I feel free of their outrageous charges but, am sorely missing my phone. Being able to use it with wifi would be awesome as all I'd need to do is find a McDonalds, and use their wifi to make free phone calls (like I was once able to do!)

These units had great technology and seemed to be dummed down for the service providers. They should have a preloaded map, and then you could use GPS, but NOOOO... then you could use GPS without their data plans.

Imagine having a regular car, that you could only go 50mph in, but would have to pay an extra $50 a month for to have the limiter taken off so you could go full speed!!

So, any help with my free phone call question would be greatly appreciated. I'm sorry for my long windedness, in this, my first question on the forum.

regards,
Marc

There are prepaid plans, yes. For example, here are Telus' plans. It would most likely be cheaper to get prepaid plans from a Canadian carrier than a US carrier, because the latter would charge you roaming AND long distance for placing calls to Canadian numbers.

Edit: I really doubt it was the OS version that broke your WiFi calling feature. It was more likely Rogers removing the free service in order to force you to add it as a paid add-on. But if you remember what OS you were running before updating, you could downgrade back to it.