Our reseller system works on a wholesale/retail model. You buy service from us at wholesale prices, and resell to your customers at retail. You keep the difference.
Wholesale prices are easy to figure: Just count the number of extensions that the business will have and multiply by $10. That is your wholesale monthly cost. Since most potential customers are probably paying about $60 a line for old fashioned analog phone systems plus more for needed extras, taxes, fees, etc, you can see there is plenty of room for you to make some money.
We also have service for residential customers starting at $7.49 a month (wholesale).