While many mobile devices today don't have DVD Drives built in anymore, most desktop units still do and if you want to be able to play DVD's on you computer it may cost you to do so on your newly purchased or upgraded Windows 10 machine.
You can download Microsoft's DVD Player for Windows 10 from the Windows Store for free unless...
- Your using Windows Enterprise
- If you do a clean install of Windows 10 instead of an upgrade, again you don't get it free
The player app is free only for Windows 7 or Windows 8/8.1 users that had Media Center on their machines prior to an upgrade to Windows 10. You also need to upgrade during the free period that Microsoft has outlined. Otherwise you will will have to open your wallet and shell out $14.99 in the Windows Store.
If you don't want to pay, try downloading the free VLC media player for Windows. This is an open source product that you can donate to and they currently have a player that supports Windows 10.