[ILUG] OSS print charging systems

[Gavin McCullagh]

Hi,

I'm looking for a reliable pre-paid print charging system.  Ideally, this
would wait until sheets had been successfully printed and then dock the
correct amount off the user (so as not to charge them if printing failed
for some reason).  

The credit handling should be 

 - user buys cards of say 50 tokens and card reader in printing station
   docks value off 

or perhaps preferably

 - a query runs on an existing SQL database to find out if sufficient
   credit is available and then docks the credit from the user's account
   when printing is complete.

I've looked briefly at PyKota which looks a bit involved.  Does anyone have
experience with it or of a good alternative system?  Any suggestions?

Gavin