Blogging/ Vlogging is a trend nowadays which can provide you a good amount of money if you get enough views and likes.
Travel Blogs
Handicrafts are so rare and antique pieces nowadays. While traveling in towns and villages, you can buy them and sell them in the cities for profit.
Sell Handicrafts
Social work and helping out the needy, NGOs have to travel for it. Joining them will give you a social cause, traveling, and money of course.
Join NGO
The hotel industry always needs staff. Take up a part time job as housekeeping, receptionist, or hotel manager, and spend your free time exploring the city.
Work in Resorts
If you've got good looks and personality, try becoming a part-time model. Take help from Social Media, and if you get selected, enjoy traveling places for photoshoots.
Become a Model
If you're great at clicking pictures, try selling the best snaps to travel magazines. Who knows which website will hire you and send you places for photography.
Well known about your city? Try helping out tourists as their guide if you have good social skills, and easily make money from foreign and domestic travelers.