If it's a crack that may have been there for a while, that you just didn't notice, one approach might be to "pretend you didn't notice it yet" and go on with your plans - with a "plan to notice it" when you can do something about it.

It may depend on where the crack is located, how big it is, and whether it affects the sound; but lots of guitars give satisfactory performance for years with "visible" damage.

Willie Nelson played his guitar (named "Trigger") for decades with a hole the size of a watermelon worn through the top. Some fans cried when they saw him using a different one recently since he'd played it that way for so long.

If the crack is where the string tension might make it worse, or if something is obviously about to fall off, it might be better to leave it at home until you can get a repair.

You may also want to consider that if a replacement $250 guitar is comparable to what you have, repairs to damage that would make it unsafe to continue playing the old one may be about as expensive as the replacement.

If it just "looks nasty" quit looking at it until it's more convenient to see about a patch.

Can you give more description of where the crack is and how big?

John