1) Calculate how many lives you can save with your organs. Pre-commit to donate enough money to save as many lives, on top of what you would normally want to donate.
2) Since you are under 18, I can see your problem. Your chances of dying where cryonics would be an option (read: not in an accident) are so tiny, it's probably OK to wait. But you can always take out a loan (maybe?) or borrow from someone.
3) Do you want to take that chance? I also believe that the Singularity will happen within my lifetime, but I am totally willing to pay ~$80 a month to increase the chance of my brain existing when it happens (even if it's only 1%).
1) Calculate how many lives you can save with your organs. Pre-commit to donate enough money to save as many lives, on top of what you would normally want to donate.
Doesn't sound like a good fix to me. Isn't the donated money necessarily taking away from some other (presumably also life-saving or otherwise valued) endeavor? Instead I'd point out that it's possible to have it both ways: freeze the brain and donate the rest. Not much demand for brain-donors, compared to kidneys or corneas.
An exercise:
Name something that you do not do but should/wish you did/are told you ought, or that you do less than is normally recommended. (For instance, "exercise" or "eat vegetables".)
Make an exhaustive list of your sufficient conditions for avoiding this thing. (If you suspect that your list may be non-exhaustive, mention that in your comment.)
Precommit that: If someone comes up with a way to do the thing which doesn't have any of your listed problems, you will at least try it. It counts if you come up with this response yourself upon making your list.
(Based on: Is That Your True Rejection?)
Edit to add: Kindly stick to the spirit of the exercise; if you have no advice in line with the exercise, this is not the place to offer it. Do not drift into confrontational or abusive demands that people adjust their restrictions to suit your cached suggestion, and do not offer unsolicited other-optimizing.
To alleviate crowding, Armok_GoB has created a second thread for this challenge.