I recently wrote a review about Sideshift.ai in which I discussed not only the exchange itself but also exchanges of its kind and why Sideshift is my favourite among them due to certain advantages it has over its competitors. Something I didn't mention but that has been a bit of an annoyance is how hard it is to find a place where you can buy Matic on the Polygon Mainnet, it's all too common that only the ERC-20 version is offered or that it's not available at all. So just recently to my surprise Sideshift added not only the ERC-20 Token but also the Mainnet version allowing users to take advantage of Polygons low fees and giving them access to dapps found on the Polygon Mainnet. 

And of course as expected from Sideshift you can buy as little as $1 worth of Matic in case you'd just like to give it a try before investing more.

P.S. If you haven't added the Polygon Mainnet to MetaMask here's a quick guide.