A few thoughts:
If you're not really using the Mac Mini, why not sell it to subsidize your laptop?
If you're running Linux {or OSX} you can SSH into your work computer and actually work in other parts of the house using the laptop. This highlights the fact that you don't necessarily need a lot of power in the laptop if you're willing to configure your other hardware to provide some services...and configuring computers to work together is some quality tinkering.
Anyway, I bought a Thinkpad X201 Tablet for less than $200 off ebay including a replacement battery. It's mostly just a matter of patience and willingness to accept that it will be used instead of new. I'm usually booting into the Ubuntu partition with Grub but have the included Windows 7 as an option [that looks like it will be upgraded to 10 at the end of the summer].
It's a bit like the pleasure [and pain] of owning an old car.
Good luck.