Price list is a compilation of destinations and their rates. Usually A-Z.
Rate plan is a set of price lists for each access point.
E.g. one rate plan may include rates for: softphone calls, calls through UK access number, callback calls. And each of these rates may be different.
Including or not including certain access points in a rate plan defines how customer can make calls using different access points.
A customer can be charged one price per minute for making a softphone call and another price per minute calling the same number but using a local access point number to make that call.