Of course each type of coins is different so it is only normal that they have different value. The first thing to do would be to have an expert evaluating your coin collecting value. I would even go further by having multiple expert conducting coin appraisals on your collection. The expert or coin dealers have the knowledge to help you find you coin collecting value. The value of your coin should be approximately what you expect to pay when you sell your collection.
As I said the internet is probably the biggest library of all to gather quality information on the subject. You can even buy some eBooks that explain in detail the process of coin grading and coin collecting value. The most important part however is to fully assimilate this knowledge so that you can understand the technical information you will be given by most of the experts who will conduct coin appraisals on your collection. You may even get lucky and find an expert who is more than willing to share is knowledge with you to further you education on the various coin collecting value grades and prices.