Background: I am in charge of a code which I've written for the office (at the direction of my manager). Our office just merged with another office a few states away. The plan is to eventually have them be able to use the software. As it states my software cannot meet this requirement reliably. So now I'm scheming up a solution.
The Problem: One such solution is to use a online server which will allow reliable access anywhere. The issue arises because this service costs money. Its fairly trivial ($5/month), but I am 100% sure that it would not be approved (business is not booming in any sense of the phrase). I would just sign up for it myself and just not mention that I'm paying for it personally when I distribute it, but I have a sense that this is wrong.
My question:
Is my gut feeling justified, or can I (appropriately/ethically) use my personal money for company benefit?
Sub-questions:
If I do get it, should I mention that I'm paying out of my own pocket?
Would it be unethical to deliberately hide that I'm paying out of pocket?
If I do this without manager approval, could it conceivably get me punished?
Important Clarification:
The issue isn't necessarily that $5/month is too much money for an international engineering firm to afford. We could afford if my manager wanted to spend it. The issue is that he doesn't, partially because he isn't very fond of my program (for a variety of reasons). This is part of the reason I feel pressured into just making sure it works regardless. But, based off the wonderful accepted answer, acting independently from management and taking control of a company resource is a poor decision