Microsoft offers only 5GB storage for free with each account, but the additional storage price seems to be so good but complicated. On their personal plan you can get 50GB storage for $1.99/month and can pay monthly and unfortunately, it's not available in every country. For personal plan visit: https://onedrive.live.com/?v=upgrade once you logged in to your Microsoft account.
But on their business plans, you can buy 1TB storage for $5/month and 5TB storage for $10/month but the condition is you need to pay for a whole year. For business plans visit this page - https://products.office.com/en-US/onedrive-for-business/compare-onedrive-for-business-plans
There may be other ways to get additional storage for OneDrive, don' forget to try google / bing search.