Oh, and no carrier, despite having the "no contract price" on the phone will ever sell you a handset for that price unless you actually were in a contract and wanted an out-of-sync upgrade
As long as 'carrier' is 'major carrier' that is likely true. I know that many MVNOs don't limit themselves. PCMobile( http://www.pcmobile.ca/ ) is a small brand, with the large backing of Loblaws (a Canadian grocery empire). They have only a small selection of phones, and they are all locked. Their prepaid rides on the Bell network, and their postpaid is on the Telus network. But at least their rates are clear, and any time I have to phone support, it really appears that they have not offshored their call centre. They do have data rates for prepaid, up to $30 for 1GB (I know, I know), but at least it's there. Two potential concerns -- the phones are all carrier-locked - which is common across most carriers anyway (unlock on prepaid is available, should be on postpaid), and the prepaid cards are somewhat harder to find - unless you go to Loblaws or a related grocery store.
It's possible to roam with various options available, but watch out for the data charges -- looks like about $5/MB minimum (!!!).
As to the point of sales? For prepaid phones, you go to the store, check the display phones, pull the card for the phone of choice, and checkout which is where they actually get your phone and give it to you. That's it. The whole setup thing happens later, typically over the phone. I've seem similar results for a straight over the counter purchase from Virgin Mobile as well. Note that stores will try and get you to move to postpaid, because that way you pay more. Be polite, but firm, and if you aren't getting what your research said you should be able to get, leave.
Since it rides on Bell or Telus, coverage does not seem to be a problem. Base rates appear to all include number ID on calls, and voice mail. Watch the voicemail one carefully - some brands appear to have a good rate, until you discover that they *NEVER* include voicemail, and you're on the hook for an extra $10 a month.
In general, I would say that you want to leverage WiFi wherever you can -- it's getting to be quite common, and apps like the Android "WiFi Web Login" will often let your phone automatically reconnect to many WiFi locations in stores and restaurants. Lock down your apps so that you know for certain what is using mobile data. It's still going to be a bit of time sink to manage it -- but that's pretty much what the carriers want. Either you use the time to manage the pain yourself, or you pay them to make the pain go away.