Vehicle Speed Sensor

I have a 98 Tacoma 4X4. 5 speed....300K miles. For the last couple years, my speedo, odo and tach would occasionally fail to work at start up. I would just shut it off, and when I cranked it up again all would work fine. I thought it was just a personality glitch. But last week, the problem became permanent, along with a check engine light. It coded as PO500.

So as I am shopping for the speed sensor, I am shown 2 different things. One of them just looks like a little piece that fits into the tranny with a female plug in....costing around $70. The other looks like it might be the same thing, except with about 30 inches of wire on it...costing around $180. Any idea which one I need? Can I test my wires and check for voltage to the sensor or something?

 

probably better off looking for a bad relay in the engine fuse box.