People might not like my response, but I'd say that if you're in a situation where you believe something might be beneficial to you but it consumes a substantial portion of your resources, you should heavily lean towards not going. This applies as much to a rationality workshop attended by someone with a tiny budget as it applies to playing the stock market. Making large expenditures for an uncertain return is generally a bad bet even if the expected utility gain is positive, if failure has a very negative consequence. And human beings are notoriously bad at assessing the expected utility in such situations.

You also need to be very confident in your ability to evaluate arguments if you don't want to end up worse than before.

Obviously, this doesn't apply if you're absolutely certain that going gives you more benefit than you forego in money, time, and parental willingness to give in (which may, in fact, be in limited supply) so there is no risk of loss, but not too many people are really that certain.