If you don't have a Gamecube...err...buy one...even the consoles aren't that expensive anymore, you can buy a second hand one for a cheap price. Go to a proper Games shop though. Never buy second hand from a dodgy retailer.
GBA/GC link cables are pretty cheap. In the UK, you can pick one up for £4.99, which is practically pocket money.
Incidently, you'll also be able to evolve your Kadabra thanks to XD if you so decide to get it, as well as use it as the middle man for trading your Hoenn and Kanto Teams around(meaning you can have a team of your favourites easier).
On top of which, you'll also get access to Pokemon with rare moves you wouldn't get in the normal games, AND by doing Mt. Battle you'll be able to get those useful stat altering berries, as well as a Gold/Silver/Crystal starter with an elemental hyper beam.
If however, you don't wish to get XD, you could always just buy a second hand GBA, and a link cable. Probably cost you about...£25 tops.