With the start of a new year, we now have visibility into summary statistics for deeded parking spaces that sold in downtown* Boston during 2008. Both average and median sales prices for Boston parking spots increased in 2008 over 2007 numbers.
2008
Number Sold: 93
Average: $80,459
Median: $65,000
Average DOM: 112 days
Approximately 20 $100,000+ parking spot sales in the Back Bay, Beacon Hill, South End, North End, and Waterfront bolstered sales figures in 2008.
2007
Number Sold: 117
Average: $71,865
Median: $40,000
Average DOM: 73 days
2006
Number Sold: 53
Average: $93,225
Median: $75,000
Average DOM: 202 days
*Downtown Boston includes the following neighborhoods: Back Bay, Beacon Hill, Chinatown, Fenway, Financial District, Leather, Midtown, North End, Seaport, South Boston, South End, Theatre District, Waterfront, West End.
Keith Munsell 
any insight into what a single parking spot on Marlborough Street goes for? The area around Hereford specifically
Alan, the most appropriate parking spot sale to compare against is 348 Marlborough Street #B, which sold in early October 2008 for $98,000.
How about parking spots at 151 Tremont St (the Tremont on the Common)?
Hank, there were more than 10 parking spot sales at Tremont on the Common in 2008. The average sales price was $58,400 and the median was $64,000.