I'm working with a startup that's teaching kids to program. We've just obtained our first "fleet" of laptops - half a dozen refurbished thinkpads running Windows 7 - and I'm looking for the best way to administer and maintain them.

I've already determined that it appears to make sense to buy a volume license key, so I can use reimaging rights and generate a single known good image I can write to all of them, and use to wipe out a computer whenever I need to. What I'm wondering about now is how best to manage them on an ongoing basis.

The laptops will run on a variety of networks - none of them controlled by us - and we've got no central office or servers. We'd rather not acquire any.

I'd like to be able to easily push out updates and new software to all the laptops, as well as doing things like remotely configuring administrator accounts, and managing patches to make sure the laptops are kept up to date.

As a tiny startup, funds are limited, and money spent on software licenses is money we could have spent on more hardware, so expensive solutions are a bit of a no-go.

Does anyone have any recommendations for how we can most easily do this?
['https://serverfault.com/questions/709346', 'https://serverfault.com', 'https://serverfault.com/users/83562/']
This is the perfect use case for [Microsoft Intune](http://www.microsoft.com/en-us/server-cloud/products/microsoft-intune/). While it is primarily known as an MDM solution, it also has PC management capabilities as well, such as app deployment and patch management. It's also completely cloud-based and is licensed on a per-device per-month basis, so it can scale as you grow. 

If you're already managing internal devices with System a Center Configuration Manager, it has some neat integration. If not, it's perfectly functional as a standalone product as well.
I'm not sure if this will cover all you need but...

At the place I am recently employed, company-issued laptops (which are running Windows) are required to be able to access the company VPN. Namely, VPN access is only allowed using company-issued laptops. 

Users are not admins on their local machine. Therefore, company IT personnel do all the administering, like setting Windows Update schedules, setting the schedules for anti-virus update, etc.

At first glance, it seemed annoying to me as a user not to be able to admin a laptop I take home or install what I want, and it probably takes the IT group some resources to manage the laptop fleet, but I suspect this methodology reduces external threats that free-floating laptops might otherwise present.

Good luck.