how to get start selling on amazon`: Marketplace offers you an opportunity to sell products on the exact same page on Amazon’s website where Amazon sell the product themselves. So you get to compete with them head-on, and even get to compete with them on price. Selling prices are fixed – Marketplace isn’t an auction. You can list some number of items for sale for free but what they call a referral fee is charged on each sale. Marketplace is for both new and used products.
Marketplace is suitable whether you just want to make some spare cash part time, but also if you want to start a ‘proper’ small business.
The other main way to make money is Amazon Associates. Associates is basically an affiliate programme.