I'm on disk 1 and I made the mistake of selling my chocobo lure and it's preventing me from crossing the desert to get to gold saucer to get the keystone, I'm at the chocobo ranch and I can't seem to be able to purchase one. I'm not sure if I can compleate disk one or get to the temple of the ancients w/o the keystone def need some advice..

Yes if you take a chocobo to across the sand you only enter corel prison. Remember that place you went to when you met Dyne? You can only find unlimited desert though as the prison itself is a once in a life time visit.

Go to Corel, north of the gold saucer and enter there. You will find a tram, you will also find that it costs money to enter gold saucer. Have fun.

Try if you want to talk to the girl in the chocobo ranch. I heard somewhere that she sells you the chocobo lure materia when you lost your current.

Go to corel, north pf gold saucer to get the the saucer and with the marsh, you can run through, completely avoiding it by running along the right wall, if the Zolom is on the other half of the marsh.