I have noticed that either unscrupulous or uneducated vendors are charging rediculous prices for very common medals sometimes up to 400% above a reasonable retail value. Before you bid do some research. Just because you haven't seen one doesn't make it a rare medal neither does it make it rare because the vendor says so. If a medal comes up you want to buy , type the details into your internet search engine and peruse the results.
Some of the details that should be considered are... Country of issue ... Type of medal.... Why it was issued (campaign, Order of knighthood, bravery etc.)... metal... date of issue.... naming.... regiment ...... Number issued to a particular regiment or for a particular campaign... Last but not least condition (medals are graded much the same as coins).
A good reference guide is THE MEDAL YEAR BOOK by Token Publishing. This book. even an old one will give you a rough price guide and an idea of what to look for when purchasing a medal.
Don't part with your hard earned cash only to find out down the track you paid too much... Remember there could be another bidder who is also a little green on the subject bidding against you. Ask questions and do some research. Knowledge is power and could save you a heap of money...
Having said all that there are still bargains to be had on ebay, I have picked up many and hope to pick up many more.
Hope this helps
Happy bidding Bob