HI! Welcome to the PF! I do 90% of my Coach purchases from ebay. If you find something you like but are unsure of just post it in our authentication thread. Or you can pm me directly and I'll let you know if its a good one or not so good.
I have purchased on ebay so many times.. I think you should be fine if you have it authenticated and always pay with paypal or something that gives the buyer some protection.. I try to stay away from sending money orders at all costs!
I've purchased on ebay quite often (I just got 2 bags off of ebay!) and have always had good experiences. Utilize all the experience here and you should be fine! It's also good to know what to look for! There's lots of information here so enjoy!
Ebay rocks, I buy and sell there all the time. Ebay is often the best or only way to find rare and/or discontinued items. As Ranskimmie suggested, if you are uncertain about authenticity, you can post your items here and let the resident Coach experts share their opinions with you.
If you use reasonable caution and good common sense, Ebay can be a lot of fun.