A friend of mine has a few John Deere bicycles and he would like to know what they might be worth. He has 4 in total. 2 are the 3 speeds in John Deere green. One is a men's and the other is a ladies. The other 2 bikes are the 10 speed bikes. One is the ladies bike and in white and the other is black in men's. All are in good condition but need to be cleaned and tuned up. What would they be worth?