RAW given the formulae of max purchase = Rep * 10 and base max Prizes = total Renown + 1, you need to have at least 1 rank in Renown before you can buy anything with a Rep cost.
Since at Renown 0, your max prizes = 0+1, not sure I agree with that reading.
Edit: Ah, I see, you meant to say Reputation cost up to 10 × your total Renown.
, your initial wording was less clear.
Ok, so buy a level of Renown if you want a prize.
Also, what about giants as a PC option?
Since we're loosely setting it in Sunchaser, let's stick to the species it defines in the AC (p.92)
Species: Drake, Dwarf, Elf, Human, Pech, Rootwalker, Saurian
Edit: Ogre, Orc, and Goblin are also allowable, however given the association with the Crone in the setting, I'm going to impose a penalty, where PCs with these Species suffer a -5 to Disposition of characters not in service to the Crone (stacks with the Ogre's Reviled, so -15 for Ogres)