Our online store options are geared at processing the order as well as payments online and simultaneously. While a service like PayPal or Google Checkout might not then be the solution for cash payments, you might want to integrate an order form for your customers by stating your bank details.
By doing this you can still manage the orders by the emails that come through to you, and when your customers receive the goods, they can then transfer the cash into the bank account you listed on your site or on the form.
The guys at Wufoo.com provide a really great service where you can build and customize your own forms and then integrate them directly into your Yola site just by pasting some code they give you into an HTML widget.
We would just like to put out a friendly reminder that doing business this way over the internet can be extremely risky. We would even advise that you avoid this method at all costs. We'd hate to see you send your stock off without ever being reimbursed.