RIR (Regional Internet Registry) deals with address space allocation, LIR registration, statistics and dispute resolution. These are non-profit organizations, they don't sell anything. However, each LIR pays membership fees (calculated based on the size of the network) in RUR. RIRs do not work with end users and individuals.There are five of them in total — RIPE for Europe and the Middle East, ARIN for North America, APNIC for Asia and the Pacific, LANIC for Latin America and AFRINIC for Africa.
The status of RIR is assigned by IANA and it is impossible for an organization to become RUR.
LIR (Local Internet Registry) are divided into categories based on the size of the network. There are 5 categories in total — Extra Large, Large, Medium, Small and Extra Small. The categories depend on the size and several other factors, and are assigned by the RIR itself. LIR pays membership fees to RUR. They are small and calculated based on the LIR class.
LIR has the right to allocate (Sub-Allocated) or sell SAN and IP/PI to its customers. Also, the LIR can be an intermediary between the end user and RIPE (for example, in the situation of registering AS\PI\LIR).
As a rule, large network operators (providers, data centers, registrars, etc.) have the status of LIR.