... Why in god's name would a pokemon version parallel to another one cost more?! >_<
If you're willing to invest some more pokedollars, buy some dusk balls. They have double (yes, DOUBLE) the catch rate of Ultra Balls at night, or in caves. They're just awesome, and even cost 200 pokedollars less than an Ultra Ball. I'm pretty sure you can buy 'em in Blackthorn, Goldenrod Department (like everything else :P), and a few places in Kanto like Vermillion.