$10 to $50, depending on condition. They were mass produced, so a lot survived. The most expensive of the older toys come from Japan. Though some pre WWII stuff can be worth decent money, due to a lot of the metal was melted down to support the war effort.
I've seen a full set selling on eBay for $2-3.
Depending on their race from 10 to 50 dollars.
$6, 000, 000
In 2010, in a 36 race schedule, Greg Biffle earned $4,966,010. in race winnings.
$50.00
They can cost anywhere from $100-800. And can get pricey.
eBay
2/1/2012 One w/ box just sold for about $180 on Ebay. It's a hot item because it was the first handheld video game ever made, 35 yrs ago.
15
It's worth whatever someone is willing to pay for it. There's a nut for every bolt.
It can be purchased from Ebay or rubiks.com, those are your best options. I haven't checked Ebay, but on rubiks.com it is $20.
You can try to put it on EBay. Some one might think it is worth something.