Move into mobile telephony. Customers get cheaper calls if they go over wifi, use a standard mobile connection if not. If you control the access points in homes

Move into mobile telephony. Customers get cheaper calls if they go over wifi, use a standard mobile connection if not. If you control the access points in homes and businesses, you can allow handsets of unrelated customers to access them. Whether this makes sense obviously depends on whether you do control your customers' wifi routers and whether you can get the handsets cheap enough for your market.