DOI, ARK and Ezid (a service of CDL 500$/yr)

EZID is a service of the California Digital Library,

Create and manage long-term globally unique IDs for data and other sources using EZID

500$/yr for DOI and ARK (1 million/yr)

DOIs
Recommended for final products, published materials, and citation. Use for objects under good long-term management.

ARKs
Recommended for projects requiring more flexibility, early or unpublished versions of material.