In Cerulean City. You have to go talk to the Pokemon Fan Club Chairman in Vermilion to get the bike voucher before you can get the bike though.
Cerulean city it has a bike shop you can get a bike for free if you have a bike voucher you can get one from the chairman of the Pokemon fan club which is located in vermilion city.
By bike
go down to the pokemon fan club near where you get your 3rd badge talk to the old man about his rapidash hell then give you a bike pass take that to the bike shop owner then you have a bike
the vermilion Pokemon fan club
The Bike Shop...........
I've never played Pokemon Red's Adventure, but since I'm assuming it's based off of Pokémon Fire Red, where ever the second gym is, since there is a bike shop there.
go to vermilion city and go to the Pokemon fan club talk to the chair man, and he'll give you a bike voucher. go to cerulean city and go to the bike shop and he'll give you a bike. PS- DONT WASTE 1,000,000 POKEDOLLARS ON A BIKE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Get to Vermilion City and find the Pokemon fan club you can't miss it its a green building with a sign next to it there is a chairman of the club talk to him and listen to his story about his rapidash once he is done he will give you a bike voucher show this to the bike shop in cerulean city to get a free bike.
get the bike ticket and bring it to the bike shop and you will receive a free bike
you purches it at the bike shop for 100,000,000 bucks
go to the mauville city bike shop!
Yes, you can