No way
Can You Buy A Light Ball In Soul Silver?
No you can't sorry. The only way to get it is in the Yellow Forest route of the Pokewalker or whatever the route is called.
I'm not so sure because I havent seen one and I'm up to the elite four
Don't be stupid that's not a pokeball that's a held item and the only way to get it is in yellow forest
No but you can get from yellow forest or from a random pikachu(5% chance) catch a pikachu then put it first in party and go to viridian forest and keep catching
No you can't. Sorry! I know this because I have already beaten the game and have been to all the Pokemarts. But there is a huge selection of other Pokeballs to choose from!