your marlin was made in 2002-2003.
Your Marlin model 15YN little buckaroo single shot,which was made in the year 1994 will bring between 80-110 dollars in the condition that you describe.
1988.
www.brownells.com
By taking the first two numbers from the serial number and searching, Im getting 1983 http://armscollectors.com/sn/marlinlookup.php
http://stevespages.com/pdf/marlin_15yn.pdf
I just bought one for $160.00 and found another one for $159.00 So I would say they run 160.00 in real good condition. Ron Nelson
Around $100. I own one as well and was planning on selling it so Iresearchedit.
The 15-Y was made from 1984-1988 The 15-YN was made from 1989-1996 It's now known as the 915-Y Here's where you'll find all the other info you'd ever need. http://www.rimfirecentral.com/forums/forumdisplay.php?f=20