I believe you have to wait until you get to Cerluan City. You know, the guy that wants to see certain pokemon.
But if memory serves, there were some people who would give you stones when you get their phone numbers or something... gosh I miss crystal.. it was my fav game =)
Whoa.... you must have a kind mom then, o.o
My mom refused to buy us a Gameboy until GBA came out. Then me and my brother added our money and made her buy one for us, but we had to pay for it ourselves ^^"