The NBER offers free working paper access to residents of countries with per capita GDP of less than $35,000 (2017) according to the IMF listing of income by country.
If your computer is in one of the eligible countries you should be offered a full-text download on the bibliographic page for the paper. If that does not happen, select the "Information for subscribers and others expecting free downloads" link and you will be given the opportunity to submit your email address. You will then receive a URL for the paper if your email domain is in one of the eligible countries.
Questions about authorization may be directed to Tim Page