Many people already made very sensible remarks on tool break; I'll just add one consideration.
Accepting the fact that it's gonna break at some point and that you'll need the money to buy a new one back: would it be easier for users to pay a small fee each time they use it, or to gather a gigantic amount of money to pay back a tool they had the misfortune to clumsily break? Don't look at a fee as something to get a profit, but rather as an insurance plan. From this viewpoint, if you want to bring a service to the community without making a profit out of it, you just need to 1) estimate how many uses it'll take, on average, for an user to break it, 2) calibrate a fee big enough to let you stock enough money to buy it back before it breaks, but small enough to keep you in the non-profit zone. This was my two cents worth.

That being said, I greatly appreciate your endeavor and I'll donate 10 nstars to your warp and I offer free ereps for those using the tool (though I can't guarantee I won't be afk when the time comes, so your users would better not rely on me for this)

p.s. your requirements for being eligible to use it are not strict at all, on the contrary: it's the bare minimum, in my opinion!

 

Argh, I misread, there's no warp. Coords?

 

What Expip says is exactly correct - the tool WILL be broke and a fee for use will help offset that loss.
In addition, I would like to recommend that your usage contract include a clause that requires the user to eliminate (or move to a very hard key to use) the "q" key or any quick drop key they may have.
I will also be donating 20 nstars to your project and offer free ereps (thru a chest only - Never throw a tool on the ground).
Wishing you the best of success!

 

This ^, much this. At first I moved it to [P], then I totally got rid of it when I realized it could be completely disabled. Why have such a risky shortcut for something that, if you really intend to do, could be done by hand in the inventory GUI?