How to have an object detect when the user spends money?

I'm attempting to create an object that warns a user when they spend too much money in one day (based on a percentage of the users money they have on booting into Second Life), and can't find anything in the wiki that tells how to have a script be called on transferring money.

currently I don't think it can be done. I don't even think you could do it out world since no email is sent on a transaction.

Sorry, I don't have time to really look into it right now but I would think that you may try to connect it to the permission settings. If you had an attachment that had a state linked to the change in permissions needed to exchange money it could be a good starting point. But again - that's just off the top of my head while skimming the forums.

I don't know a lot, that MAY work for paying an object, like a vendor, I don't think it would detect when someone buys something using the in world tools.. When they set a price on the object..

There is currently no LSL function that lets you monitor a user's funds.

However, you could possibly script a program on an external webserver to interface with LL's online account monitoring tools.

good call and yes that would work, you could even pull it in world but it would take some effort .