alternative to using a sequence

I have an application that processes financial transactions. Each of
these transactions needs to be sent with a sequence number. It starts
at 1 and resets to 1 once it hits 8000. I'm trying to think of the
most elegant solution without having to create a sequence for each
user (there are hundreds). There is a table that holds the
configuration parameters for each merchant, so a field in that table
to hold the sequence number would be ideal. In the past I've used
sequences as well as just a field which I query then update. Any
other ideas?