I want to put a item on ebay to sell but it keeps coming invalid value what does this mean ?

[rainbow*rob]

everytime i try to put an item on ebay to sell , it keeps coming up invalid value.    what does that mean and how do i fix it ?

[pmlinne]

Could you have written $ in front of the number?  I've done that before and since the $ is already there, I get the message to put in a valid number.