The collector auto market in the US just continues to expand with the values of vehicles seemingly only growing in the past years, especially if they have a prancing horse on the hood. This year was no different. According to data compiled by classic car insurance agency Hagerty, there were about $1.3 billion worth of vintage rides auctioned in North America in 2014, up just slightly from $1.2 billion crossing the block in 2013.If you want an idea of just how big a role the Monterey Car Week plays in the North American collector hobby, Hagerty's stats illustrate it perfectly. The company recorded $ 430 million in auction sales during the week – about a third of the entire market for the year. The event also hosted the biggest seller of 2014 when the hammer fell on a 1962 Ferrari 250 GTO (pictured above) for $38.115 million at Bonhams.In fact, vintage Ferraris in general were among the top buys in the classic auto world in 2014. Eight of the ten most expensive vehicles sold at auction were Prancing Horses (the other two were Ford GT40s ). Also, the insurance company's price index for these Italian stallions showed a 43-percent gain in value for the year.The market for another Italian supercar is exploding, as well. The Lamborghini Countach showed a staggering 175-percent growth in auction value in 2014. According to Hagerty, the average price when they crossed the block was $736,599.Judging by Hagerty's numbers, there were still some places to look for those hoping to spend a bit less money. The Aston Martin Lagonda showed a strong gain in value with a 32-percent increase in auction price, but they still averaged $47,078. In addition, the company's index for '50s American cars showed only one-percent growth for these classics.These huge leaps in collector car value might be winding down, according to Hagerty. It predicts growth in the market to slow to an estimated five percent gain in 2015. Maybe a few of these classics might actually become a bit more affordable to fans without such deep pockets sometime in the future.