Could you make it like this? :
sos can be dropable
som/sun could be for high price (gold from trade runs) + arena coins.
Low gold rate (For eliminate gold bots and lead mbot users over legits)
Rates about x100/x120 (exp/sp)
Job x80 or higher. (Sun weap should be able to buy after 5-7 5* traderuns, so you have to test how much gold will give one 5* run, and then put adequate price for items

)
Thank you.
Another idea :
sos can be dropable
som for gold + arena coins
suns from FGW, but u have to fix quest!