When purchasing PAXG on Paxos.com, the minimum purchase is 0.03 PAXG, due to the conversion fee of 0.02 PAXG.
However note that there is no minimum amount of holdings for PAX Gold (PAXG). PAXG is divisible out to 18 decimal places, so it is possible to own fractional amounts.
You may note that for small fractional purchases of PAXG that the fees charged on the exchange order book will be much less than the fees charged if you purchase via the Paxos Wallet. You may find more information in our PAX Gold fees article.