1. From the Old Rod Man:
* You need to reach Goldenrod City.
* Go to the department store located in the city.
* Enter the fourth floor of the department store.
* You will find the Old Rod Man at the back of the floor.
* Talk to him and he will give you the Old Rod for free.
2. From the Game Corner:
* The Game Corner is in Goldenrod City.
* You can earn Game Corner Coins by playing the various games within the Game Corner.
* You can then use these coins to exchange for the Good Rod at the counter.
The Old Rod is the basic fishing rod, allowing you to catch weaker Pokemon. The Good Rod is an upgrade, allowing you to catch stronger Pokemon.