Perhaps I am supposing too much. How often is it that founders run around without insurance?
For the US and Canada the easiest thing is to let an insurance professional work out the details for you, get several quotes that give you the kind of coverage that you need and then sign up with one of them.
It may significantly change the picture if you incorporate first, then get a corporate health package for your startup and register yourself as an employee.
Remember about special circumstances such as business travel if you are going to spend a lot of time en-route.
Another big factor for self-employed people is insurance that covers you in case you become incapable of working, but personally I've never been able to justify the expense of that kind of insurance.
If you can, save up. I know that's weird advice to someone starting out because you'll need every penny you can get to make it go, but even so, if there is any chance of it, create a little nest egg, you never know what's around the corner.
It may help in some respects, but in others it might actually be detrimental.
One of the beautiful parts of working via the internet is that you can do it from just about anywhere. Plenty of start-ups and open source companies work without a formal office, the founders are where ever they were living before they got together and formed a company.
I disagree somewhat about only needing coverage for catastrophic illness or accidents. There's a huge psychological benefit to not having to do a cost/benefit analysis if you think something's wrong and you want to go to a doctor.
In the U.S., for those who are young and healthy, and with an income and/or savings that can cover routine and significant initial expenses, I've heard it recommended to go with a major medical plan having a high deductible (multiple thousands of dollars). You pay for all the routine stuff yourself, and for the initial hit for anything bigger. If you encounter a catastrophic situation, you are covered (beware of pre-existing conditions when you sign up). The risk of that is relatively low. Rates are commensurately lower. This corresponds more with how medical insurance was for many some decades ago, before coverage was in practice extended to routine expenses.
It's the expense of a catastrophe you need to worry about. If you end up tapped out, families and, if necessary, friends can usually find a way to cover a few thousand dollars until you hit your out of pocket limit.
Most likely, there are people who care about you. Carrying health insurance isn't just about you, it's also about them. You prevent putting them in a bind where they must exhaust their own finances to take care of you. (Of course, these days the way insurance companies reprice and drop policies limits the longer term efficacy of self-insurance while unwell, but it's still a valid argument.)
Years ago, I heard that (again, in the U.S.) the IEEE had some group plans that weren't terrible. But that was second hand information, from someone well into middle age (and so in a different part of the market), and times change.
Finally, a number of people I know with their own small businesses obtain their coverage through their spouses or significant others, who work a job that provides a group plan. I'm not saying Plenty of Fish nor eHarmony is a plan of approach, but if you are in a long-term relationship with someone having coverage, even if not married, it is worth exploring what that plan may offer. My last employer covered long-term partners (although I'm not sure how that was qualified; I believe sharing a household may have been a factor).
EDIT: One more thing: I think that COBRA may now cover students for some number of months after they leave school, as a continuation of their coverage e.g. under a parent's group coverage from work. I could be wrong; perhaps someone else can speak to this.
If you are just leaving school, this would be looking into; it would give you a year or 18 months or whatever, as long as you can pay the monthly premiums. However, you must elect COBRA coverage within a relatively short period of the time at which you qualify, or you lose the option -- at least that's how it is when electing COBRA after leaving an employer.
Also, if you submit doctor's bills through your insurance company, most of the time the insurance company will negotiate a better rate. So, even if you haven't met the deductible you'll end up paying less.