Depends what you mean budget. I only know of efi and photogate, but I'm sure there are cheaper options out there.
Agreed - budget is a bit open to interpretation.
Perhaps cheap or free would be more accurate ;-)
Cheapest I have found is 'Shiraz' at £350. Not on my budget; was hoping beyond hope for a online giveaway or something similar that I just missed out on when buying my 3880. They gave away a RIP for the just a few months after my purchase. I was not able to acquire on after the event :-((
I would like to print longer panos than the A2 format will at the moment will allow. 37" is a theoretical max using the epson software. Always wanting more than I have- typical!