Of the first 16 cars (sometimes called the "Sweet 16" by collectors), 10 were based upon customized versions of regular production automobiles of the era, and 6 were based upon real show cars and cars designed and built for track racing. All of the cars featured "Spectraflame" paintwork, bearings, redline wheels, and working suspension.
These are the first ten:
Cars released in 1968
Custom Barracuda
Custom Camaro
Custom Chevrolet Corvette
Custom Eldorado
Custom Firebird
Custom Fleetside
Custom Mustang
Custom T-Bird
Custom Mercury Cougar
Custom Volkswagen
http://en.wikipedia.org/wiki/Hot_Wheels
The earliest Hot Wheels cars are now 33 years old and have become the premier die-cast collectible, achieving incredible prices on eBay and other venues for mint and rare pieces. (A recent private purchase of a Pink "Rear-Loader" Beach Bomb was estimated at $70,000.)
Although not all Hot Wheels cars are valuable, the average sales price for 1968 - 1973 issued cars is between $40 and $100. Rarer cars often trade for between $150 and $500, and some of the rarest pieces sell for up to $22,000.
http://www.auctionbytes.com/cab/abu/y201/m07/abu0041/s06
Wingman