How?

[pkmn17]

Do you catch all 200 Pokemon in R/S/E without a cheat device cuse i don't have many friends that play pokemon.

 

[Raito]

Get another Gameboy and a Link Cable, and the opposite game, and trade. If it's in your budget.

 

[Krug]

You can't you're just gonna have to wait until wi-fi trading comes out.Then I'll trade you the ones you need.OR you can get more friends...
EDIT:SORRY!I was thinking jirachi and deoxys...

 

[pkmn17]

Get another Gameboy and a Link Cable, and the opposite game, and trade. If it's in your budget.

I would really love to get a DS/DSL(Lite) but seeing to how it's $129 where i live i will have to wait till X-Mas.

 

[Raito]

DS doesn't trade with the Gameboy Games, but a used SP is about 50-60 bucks. A new one is 70, and a link cable is 10 bucks.

All estimates.

 

[Snaggron]

Well, Yes you can catch the Hoenn Dex 200 just between Ruby and Sapphire...

But for the other 186 you need FR/LG/E/Colos (Ho-oh)/XD (Lugia).

 

[shooting star]

Snaggron are right!
After what i have heard you dont need Jirashi, Celebi, Mew and Deoxys for completing. If thats true, im VERY happy!