Hi Benjamin, 

Yes it's possible to get volume licensing for your 50 machines.
At the moment you can get Windows 10 with downgrade options to Windows 8.1 or Windows 7 and this allows you to legalize your windows 7 and when you are ready to upgrade to win 10 you will still be compliant.

With office you have two options
1. Perpetual licenses where you can buy one off version of license e.g office 2013, 2016 etc this will be valid until Microsoft stops supporting it. This could be expensive to procure (Capex) no running costs (Opex)
2. Subscription licenses where you pay monthly, or annually and ownership ends with expiry of period paid for.  This has no Capex but has  Opex.  Cheaper in the long run especially when you need to upgrade and flexibility for paying for what you need e.g a staff resigns and you don't need to pay for his/her license for the time the position is vacant if on monthly payment. 

Pricing for any of the licenses is based on
1. Type of license I.e Home,  Standard,  Professional and Enterprise each packaged with different options /features and or capabilities.

2. Organisation type I.e Commercial /Private,  Government,  Education,  Non Govt

We can send you a quote offline.

Regards
Jeremiah