Connectionless means the data goes, without previously establishing the circuit. It is connectionless oriented. It also contains a header which describes the Network layer protocol being used, so it can be used in a multi-protocol environment without confusing routers and gateways. This is the main issue when deciding on what level of service to use. The next issue is often budget.
Costs vary widely depending on the phone company involved.
The prices shown below are from a phone company in 1996, and are only meant as being wildly approximate. Three options are discussed below, but they are not exhaustive of all the options. See the next section for more details. These three examples are meant only in the most general sense. Whether you have a 50K asynchronous modem, a dedicated 56K digital line, or a 64K ISDN channel, that is close enough in horse shoes to be taken as equivalent here.