Is it at all possible you can outsource the fulfillment/shipping? I understand that you don`t have enough business to hire, but if you can find a firm you can outsource to, it is possible they will charge you on a per-unit basis. This way, you are being hit with variable costs instead--your profit margin will shrink a bit but you never have to worry about losing money with variable costs as long as the margin is positive. Additionally, your time is freed up. Hiring someone is more permanent where you expect stable business. But outsourcing might allow you more flexibility when your sales are a bit less stable.
I can`t specifically recommend any fulfillment firms, but maybe it is something you should look into.
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