In Pokemon Red and Blue, if you're too poor to enter the Safari Zone, you're locked out and have to find some way of making money.
In Pokemon Yellow, the attendant will let you in for cheap or for free if you're broke, giving you a reduced number of Safari Balls to compensate for it. This allows you to at least get the Surf HM and the Gold Teeth while having no money.
In Pokemon Red and Blue, if you're too poor to enter the Safari Zone, you're locked out and have to find some way of making money.
In Pokemon Yellow, the attendant will let you in for cheap or for free if you're broke, giving you a reduced number of Safari Balls to compensate for it. This allows you to at least get the Surf HM and the Gold Teeth while having no money.