Internet is full of opportunities. Nowadays, almost all the offline job opportunities are also available online as well be it tutoring, designing, graphics, writing, promotions, etc. There are lots of legit jobs over there which could give you a handsome pocket money. What all you have to do is to decide your area of expertise or skills and the time you want to devote to the job, thats all.
One could easily find online jobs in the field of writing and content creation (articles, blogs and academic write ups), website designing (its really trending these days), tutoring (there are lots of websites hiring tutors to cater services through their platform), lead generation, social media account handling, data entry, virtual assistant, transcription, review writing, survey taking etc. What all you can find as offline job is now also present in form of online jobs which you can do from the comfort of your home in the spare time.