Cryonics is the industry and technologies that can provide long-term low-temperature storage of your body and mind following death. The balance of evidence presently favors the supposition that vitrification of cryoprotectant-infused tissue, avoiding ice-crystal formation, preserves the fine structure of neural cells in which the data of the mind is stored. That is the core of the matter: whether cryonics preserves the mind well enough to allow future technologies to repair and revive suspended people. If you are going to die prior to the advent of rejuvenation biotechnology, and this is a significant risk for most of us, then cryonics and its uncertainties are the only shot at a longer life in the future. It's a very reasonable wager, all told: a bet that the future of technological progress will continue, versus the certainty of oblivion found in the grave.
Cryopreservation is modestly expensive if you pay in a lump sum: usually more than $100,000, depending on which provider you go with and the details of your arrangements. Most people fund this service via life insurance, however. If you obtain a policy early enough in life the monthly payments are very cheap. It's not a terribly large amount of money even if you start in mid life.
Cryonics should be far more popular than it is. The cost is reasonable, any number of other businesses with multi-decade customer lifetimes prosper, and the potential upside is considerable. Four decades after its emergence from amateur practice into professional practice it remains a niche industry, while billions have gone to the grave over that same span of time. You might compare this with the same puzzling lack of interest in extending life through medical technology: at times one is forced to conclude that most people just don't care about living longer.
A generally favorable, well-researched, long article on the cryonics community recently emerged in the alternative online press. I think it's worth your time to read it all, and if you are presently trying to persuade anyone to see the merits of cryonics, then this would an excellent piece to pass along:
Some things should not be left to the last minute. For instance, having yourself frozen. The act of being preserved in a giant thermos cooled by liquid nitrogen in the hopes that the scientists of the future will figure out how to revive you and repair whatever it was that drove you to require freezing in the first place is no small matter. There are insurance policies to settle upon. Legal documents to notarize. Relatives to appease. And all of this must be done far enough in advance that arrangements can be made for a field response team to reach you on your deathbed and stand by until a doctor declares you medically deceased, at which time they will leap into action and begin your cryopreservation.
Legally speaking, cryonics is okay because it's considered an extravagant funeral practice. Its few practitioners would not argue with the notion that the procedure would be more effective if started before the heart has taken its final beats, but to do so would be illegal, even if the soon-to-be-deceased is a willing participant. Thus, the process waits for death, and the longer after death it begins, the worse off you are. This is why the Alcor Life Extension Foundation really doesn't like to accept last-minute cases.
One thing to note is this news of funding and initiatives presently in the works. You might not be keeping up with this sort of behind the scenes progress if you're merely interested in cryonics rather than being an insider:
If ever a group is going to coalescence behind the idea of obviating death as we know it, it's the one currently ruling Silicon Valley, which came of age at a time when it really felt like the right combination of smart people and money could solve any problem. And the most intriguing name to sniff around cryonics publicly is Peter Thiel, the billionaire investor who co-founded [PayPal] and was the first outside investor in Facebook. Thiel, who has made no secret of his belief in experimental science, and of his interest in technologies that could suspend or eliminate aging, has a separate fund set up to invest in more outré scientific endeavors. And Breakout Labs, as it's known, has provided seed capital to two cryonics-related start-ups founded by former Alcor employees.
Thiel (who declined an interview request) was also part of the conversation that laid the groundwork for a cryonics X-Prize that is currently in development. The prize, as constructed, would challenge applicants to freeze and then thaw a human organ so that it returns to a viable state. This would enable organ banks, potentially solving a huge global problem - the shortage of organs for transplant - and would be the first proof-of-concept that large, complex collections of tissue could be stored indefinitely at low temperatures without damage. It's not a huge leap from there to imagine the same thing being done with a whole organism.