I would have put $500-$1000 down on my VISA to have right of first refusal until the next day.
When my salesman contacted me about an executive-driven GT that BMW Canada made available to dealers, by the time I figured out what GT was (I had him on a 2011 or later 'loaded X3' watch) and wanted to have a chance at it, another salesman had already accepted a credit card deposit on it. Fortunately my dealership had secured 9 of them and I was offered the chance on exactly the same model with even fewer miles (only 2500) so I immediately put money down via VISA and that is the GT I have today. I learned that there was a lineup of two more people after me on mine. (Incidentally, my dealership targets 2-3 GT sales (CPO or new) each year and in 2012 my salesman sold 7 of the 9 GT exec vehicles obtained by the dealership and two more new ones on top of that).