I recently replaced an electric antenna that was very broken. It was dumping engine/spark plug noise in to the radio and it made the radio sound like shit - almost unlistenable at idle.
In order to replace a power antenna with a whip/standard antenna you need a mounting base. This is what the taco whip mod does. You dont have to buy the taco whip antenna, you can buy a super cheap $10 antenna from the parts store, but in order to mount it your going to have to open up the fender, remove the old antenna assembly and install the new one from the stealership. I just paied $85 CAD for the assembly and they wanted $50 for the Antenna too, but I cheaped out and bought a no-name antenna.
If your really trying to do it on the cheap, and you have some fab skills, you could rip out the old power assembly and fabricate a new mount. It would have to be isolated from the metal fender though. As in plastic/nylon/whatever non conductive material between your antenna and the chassis. Maybe you could reuse some of the plastic from the power antenna??