Recommendation for a Purchase Order package/system

[BrooksR]

I'm a developer and have a non-profit customer looking for an easy to use PO system. They are not looking for anything too fancy - enter a requisition, have one or two levels of approval based on dollar amount and print a PO for the vendor. Their budget is $2,000. It would be installed on a network and needs to be multi-user.

Any suggestions would be appreciated.

Thanks,
Brooks