We live in a country where our income is limited. How can we afford to join?
Are you considering membership based on your personal income or business income? If you manage a hotel or tour company (for example) and charge your customers in US dollars, Euros, or Australian dollars (for example), then your pricing is most likely at a premium level to match the expectations of customers arriving from these more affluent areas. Remember that our membership starts on a free basis.
If this doesn't suit your situation, then please consider applying for a grant from your tourism office, the United Nations World Tourism Organization, or USA or EU aide charities, or economic development organizations that typically fund an expense like this as education, training, or economic development.