Upwork: This website offers a great marketplace for selling just about any professional service. You don't need a merchant account, website of your own or anything else for that matter. All you need to do is be able to provide a high-quality service at a reasonable price. But be informed, you will have to compete with many others that are constantly bidding on open jobs.
In case of the latter, you will have to spend money on domain name and server hosting space that can cost you between Rs 3,000-Rs 5,000 a year. Self-hosted blogs have an added advantage that it allows you to customise elements and functionality of your website. In case of the former, you need to make peace with the tools and plug-ins made available by the service provider.
One may sign up on websites like Vedantu.com, MyPrivateTutor.com, BharatTutors.com, tutorindia.net as an online tutor by creating a profile, and listing the subjects or classes you want to teach, how much experience you have, what your qualifications are, etc. Some of the platforms may offer flexible and convenient time to work as an online tutor.
You can sell your ebooks through Amazon's Kindle program or Apple's iTunes Connect, which gives you access to a large majority of the digital-book reading market and the barriers for entry are incredibly low. You don't need to invest lots of money to make this happen, but you do need to invest lots of time, not only in writing the ebooks, but in marketing them as well.
If you have pop-ups and optins on every page, I would have to think that it would be a lot harder to convince someone to link to it. Especially since the pages where you have your optins (and probably receive the most traffic) are probably the same pages that you have your best content on as well that you'd be hoping to pitch in your outreach campaign.