I inadvertently bought an app I do not want or need. Is there a way to have it returned?

The official position is that all purchases are final - after all, you can hardly return it unused. If you contact Support and explain the situation they may agree to refund you as a one-off concession (though normally it's done if kids have purchased an app without permission, or someone has made a mistake, rather than just changing their mind); please be aware that they are under absolutely no obligation to do so. Go to https://getsupport.apple.com . Click 'See all products and services', then ' 'iTunes', and then 'iTunes Store', then 'Purchases, Billing & Redemption'.