I've been surfing Ebay and the "Cheiron's Warriors" book is for sale for $25.58. Not the best price ever, but they're hard to find now. http://cgi.ebay.com/Young-Hercules-Cheirons-Warriors_W0QQitemZ8008206155QQcategoryZ279QQssPageNameZWD1VQQrdZ1QQcmdZViewItem

Apparently there's a hardcover version of "Cheiron's Warriors" for $9.29! I'm tempted to buy it myself even though I already have the paper-back version ^_~ http://cgi.ebay.com/DeCandido-Keith-R-A-YOUNG-HERCULES-02-CHEIRON-NEW_W0QQitemZ4578086549QQcategoryZ378QQssPageNameZWD1VQQrdZ1QQcmdZViewItem

Mission From Zeus is going for $18.85
http://cgi.ebay.com/Young-Hercules-Mission-From-Zeus_W0QQitemZ8014445323QQcategoryZ279QQssPageNameZWD1VQQrdZ1QQcmdZViewItem

amazon.com has them for less in the marketplace. that's where i got mine. they have the ares alliance also.