abii, Crystal Bass is only 2000~3000 gil on AH, so you should be able to get the gil easily by doing some Field of Valor, or even hunting orcs in Ghelsba for gil and drops to sell to NPCs.
Alternatively, you could go fish them up yourself if you got a decent rod and some bait.
What you could also do, is do a shout for it near the AH. Someone might actually buy it for you, since it's peanuts for higher level players.
No PUP, no glory! <Inferno Claws [4563/3520]>
"Puppetmaster was our last best hope for peace. It failed.
Now it's our last best hope.. for victory!"