It's great that you're trying to find cheap options for those students, but to be honest, that's a side issue.

The main issue is that you have what may be an unreasonable expectation about the resources available to these students. They don't have a computer at home, which means their family probably cannot afford to buy one, and even if they manage that, they may not be able to afford internet access. Before you make requirements for papers to be typed and submitted online, or assign materials that can only be viewed online, consider the following:

1. Does the school have computers available before or after school, or during a free period (if the student has one)?
2. Even if the computers are available, does the student rely on school buses that are scheduled too close to the start and end of the day for them to make use of the computers at school?
3. If the public library has computers available, are they in good enough condition and do they have the necessary software for your assignments? Will they charge the students to print out their work? What are the hours of the library, and is public transportation good enough that students can reasonably be expected to get there (if you live in many parts of the country, don't bet on it!)

Remember: these students are already at a huge disadvantage, and even though you' mean well by trying to find cheap options for them, it may not be good enough. But you are obligated to provide these students the same ability to succeed as the others, and that may well mean changing your plans. It may be more work for you, but if you're not up to it, quit now, otherwise you're just helping the system screw those children.

I recommend Golden Frog's VyprVPN service. I get their basic service as part of my Giganews subscription. There are cheaper alternatives (their service as a standalone option starts at $15/month), but they now have 8 endpoints, 3 of which are in the US. I use them at home to access sites that limit access to people who aren't in the US as well as using the closest local service whenever I'm traveling and stuck with open wifi connections.

"FAST on Linux is fucking awesome" I'll have to share that with the rest of the support team.

Speaking purely as an individual, I wish Microsoft wouldn't have gone this way, although obviously it doesn't surprise me. On the bright side - for your organization at least - you've got another 8 years where we'll be supporting ESP 5.3, so you have a few years before you have to worry about finding another solution, or deciding that maybe running a few Windows servers wouldn't be too bad. Just saying. :)

Computers are wonderful tools, but for most subjects students learn at that point in their lives (middle/high school in the US), computers aren't necessary.

Think about the primary subjects - Math, Science, and Literature/Writing - where do you see the benefits in using computers? Obviously for English classes, having access to computers to type papers is handy, but it's hardly necessary. Computers can be used in math to help illustrate concepts, but you don't want the students using computers to do their work, otherwise they won't know how to do it without them. And much of science is math - again, not something you want students using computers for.