Adding line-in jack for 2005 model?

[caitlin]

I have a 2005 model Prius without a line-in jack (didn't think I'd need it at the time, but now I would like to get it if possible) and was wondering how difficult and how expensive it would be to get one installed.

I've tried using those FM transmitter things and found out I really don't like them.

Does anyone have any tips or advice on this?

TIA.