Both of the "free" and "don't have to pay" responses made me laugh in a bad way. Like the "Free phone with 2-year contract", or the cable companies that claim a less expensive rate on the bill but then charge a perpetual leasing fee on the mandatory equipment that, when totaled, brings it up to a higher number.
In the US, the average health insurance plan is going to cost about $6000/year. If you want better than average, you will need to pay more. If you want minimal coverage, you can pay less. Out of curiosity I looked up some health plans in my state, there are the low-risk high-premium plans that run about $3000/year, and there are the high-risk and the low-premium high-coverage plans that go up to about $15,000/year.
According to the Interwebz: In the US, a family of four with an employer-based PPO, the average employee will contribute $3,492 in premiums and $2,675 on copays, etc.
That's about $6167/year on health care in the US on the average case.
WOW! That is a lot, always assumed insurance was like $300 or something. eek!
Even in UK, that is enough for 1 or 2 private treatments and maybe even a little botox. any non-cosmetic treatment, surgery etc is free
From the Interwebz: Citizens of the UK pay 11 percent of each pound they make in weekly income between £100 - £670 for the NHS, plus an addition 1 percent of income over £670 a week.
So for most well-paid professional programmers you are looking at about £90/week in taxes for the medical system, or about £4680 per year. With currency exchange that is $7222/year in the UK.
I'm glad I'm living in Sweden where we don't have to pay for stuff like this.
According to Wikipedia, Sweden has the highest individual tax rates in the world, coming in at 57%.
Again from the Interwebz: Sweden is a nation with extraordinary high tax rates. The average worker not only pays roughly 30 percent of her or his income in direct taxes, but additionally, close to 30 percent in indirect taxes. ... Per capita government expenditure on health at average exchange rate (US$) 3044 (2005) Out-of-pocket expenditure on average at average exchange rate (US$) 1125 (2005)
So there's a total of about $4169/year on health care in Sweden.
That rate is cheaper than both US and the UK. Good job on that part.
The point of this is that even for countries like the UK or Sweden or Australia or Canada, health care is not free, but is instead paid for via taxes.
Getting back to the OP:
You can play the numbers game and hope that you come in below average. You are young and have no children so that immediately puts you below the average case. So being below average, you should expect to spend something less than $6000 on personal healthcare expenses over the course of the year.
There is a huge risk with playing that game: You may not be below average. Flip a coin. Heads, you saved a small amount of money and have good health; congratulations. Tails, you suffer serious medical problems and also end up in the poorhouse, or bankrupt. Or worse.
This is NOT a good game to play.
Insurance companies are managed and regulated on a per-state basis. There are sites like HealthInsurance.org where you can look up the insurance options specific to your state. You might qualify for state-sponsored programs if you have no job or if you have low income. Look in to those programs. They will probably cost you some money, but it is cheaper than being on the catastrophic side of the coin flip.
You can also get private insurance. Most likely your private insurance will cost more than an employer-sponsored system, so expect to pay around $7000 per year. You might get lucky, and say "I had no medical issues this year", and feel like you overpaid. Or you could be like lmbarns above, have your head cut open in an emergency operation, and then spend time on your knees thanking God that you paid the relatively small amount of money for health insurance.
Personally, I do not see it as "should I get insurance?". I see the question as "Which plan should I purchase?" Invest the approximately $6000 in an insurance program that fits your own lifestyles and risk tolerance.