Dumb question of the day

I've got a 123 car with the stock speakers. However, the radio I had in the car went bad and I currently don't have the $$ to replace it just yet. So, currently, there's no radio in the car.

My idea was to take the wires that went from the head unit to the stock speakers and connect a 1/8" headphone jack into them instead, and then take this jack and plug into a portable CD player. This would allow me to at least have something to listen to on the road prior to getting the $$ for a new head unit.

The only thing I can imagine going wrong is the portable CD player not having enough power to get everything to the speakers.

I know this is hokey, but again, it's only temporary (we're taking a trip to L.A. next week and without music, I tend to get really sleepy on long trips). Any thoughts on this?

Thanks in advance!