All payments are done online via Bluethumb. Never pay an artist directly via EFT. Once the you've agreed on the size and price, the 30% initial deposit is paid by purchasing a gift voucher on Bluethumb. You will receive detailed instructions by the artist (or the Bluethumb team).
Once the artwork is approved and ready for purchase, it will be listed online for sale and you can use the deposit voucher to pay the balance payment.