Ok, saving money is good. Your ECU (some call it a PCM) is on the firewall on the passenger side of the engine. Its kind of rectangular with a big electrical connector attached to it. The connector is held in place with a bolt. Got to remove the bolt and then the screws that hold the ECU to the firewall. Pretty easy. Anyway please disconnect the battery ground cable first, this should avoid any electrical accidents. What engine do you have? Why do you think the ECU is bad? If you buy a new ECU most parts places will not take it back if it does not work for you. Sometimes a good way to go is with a junkyard ECU. They might take it back but it will be cheaper! Good luck, tell me how this works out for you!