After you beat Giovanni you should have all eight gym leader badges. With the badges you go to Viridian City and go to that guy who taught you how to catch a Pokemon with pokeball (he's on the left side of the city). Once you find him you will go to the left and find this building at the end of the route. Travel through there and it will lead to you the Elite Four.
Well, if you think you're up to it, you can take on the Elite Four. Otherwise, you'll have to keep on training
You can't buy it. You get it after beating giovani in safron city in the silph co tower.
Giovani's in the basement of team rocket's hideout place. He's at the end of the building
The celadon city badge AKA the Rainbowbadge courtesy of beating Erika at the celadon city gym.
in which Pokemon game? if it's heartgold and soulsilver, you have to beat the game first by beating the elite four and champion. then, you can go to the kanto region and you can find celadon on the map i think.
After beating Lt. Surge at Vermillion City and acquiring the Thunder Badge, make you way to Celadon City to win your Rainbow Badge from Erika.
The city next to Celadon City is Saffron City
Gary does not appear in Celadon City.
To get the Marsh badge by beating Sabrina, the gym leader of saffron City. To get to saffron city, you should get the tea from the old lady in Celadon Mansion and give it to the guards to saffron city then, You have to defeat Giovanni in Celadon city game corner, the Pokemon tower in Lavender, and Silph Co in Saffron. Then beat Sabrina's psychic pokemon
I'm pretty sure you go to Celadon City to try and beat Erica - or was THAT the 3rd Gym Leader?
beat the rockets in celadon (search the poster) and giovani will give you the silph scope, go to the Pokemon tower and use it
It is in celadon city inside celadon condominiums
You can't go to Celadon city in Pokemon Pearl. Its from an earlier region.