Change making for evil dudes

[Asscastle]

I'm an Iksar SK. I'm at a nice leveling spot near Steamfont Mountains and I can vendor at the druid ring. Only problem is: the only item that can convert gold into plat is a spell that buys for 8plat and sells for 3 plat. A gigantic loss. I can't get my gems to show up on the vendor list either. How can I make an item with a close buy price/sell price over 1 plat (like a cracked staff) appear on the vendor's list? My pearls don't work: they sell, but don't show on the list. What governs whether an item appears on the vendor's inventory?
PS: I'm drunk, so explain it to me like I'm 5 (and drunk)