The age old answer to the age old question of what an item is worth, is "what someone is willing to pay for it".
The main factors in determining price is the condition of the item, how scarce it is, and if any boxes are available.
Your best bet in determining approximate value is to look at online auction sites. Search the internet for similar items that have been sold, and you will get a fair idea of what your items are worth, if they are in a similar condition.
Larry