Just to help you thinking: if want to make money, whether it makes sense.
If your target customers are retail... $10 probably can't make money, even if mass-produce... The key is low-overhead, everything automatic. Mass-produce a good design, still you want low/flexible inventory.
If target is business: they put on their logo as marketing pieces and send to customers. Bigger quantity, your cost should be lower. You want to be on-demand, quick turn-around... You might be able to make some money, but this is a very competitive niche as well. As YX suggested, you want to mass-produce, and leave the customize touch to the last...
You will find out in the end, if you want to make money, it's not about 艺术 anymore. If serious, you still need to know: how much material, time, space... for a piece?