I receive the same question a lot, so I'm going to put the info right here, hopefully it helps you out, and maybe even stop you from getting ripped off down the road. There are not many collectors of these, forcing sellers to drop prices, and info is even more scarce. 

NFL mantua train value. 

Each team/car is valued solely on how many were produced. The NFL abruptly ended its licensing agreement with mantua mid production causing some teams to be rare and highly sought out.  Below is the value of each team if it is in mint condition with a perfect box.  Boxes especially the gold ones are interchangeable, so the box does not add to much value but it adds a little bit.

Minnesota Vikings- $120 

Buffalo Bills- $100

Seattle,Detroit,Grey Eagles,Denver old helmet - $90

Tampa, San Diego, Patriots old helmet, Saints,Bengals -$75 

Oilers,Browns, Dallas mis print, Ravens - $55 

Los Angeles Rams, Arizona Cardinals, Patriots New helmet, Atlanta, White 49ers- $30 

Eagles white, Jacksonville, Carolina, broncos super bowl, green bay super bowl, st. Louis rams - $15 

Chicago, Dallas,Pittsburgh, Kansas city, Raiders,Packers, Giants,Jets,Washington, Miami, 49ers. - $5 or less 

Colts, Phoenix Cardinals -$1 

Only the Dallasmis print has value, all other "errors" are valueless. They're trains, not the fenderal reserve mint. 

I hoped this helped you. If this info upset you, sorry for bursting your bubble.