Page 4 of 50. Get exactly what you ordered.

Silver dollar on my 40" monitor - standard size CD lower left.
If you decide to buy coins be sure you look closely! This is an actual image from eBay on my 40" monitor. Remember, if you buy a 'certified' coin, you wont need to worry much about the authenticity nor the grading - that's why it is called certified.

Eye appeal vs. condition. Why you need the above large view (or similar) is to make sure what they sold you is what gets delivered. Unless graded as a perfect 70, all coins will have some minor defects from shipping and handling by the mint. The more defects, the lower the rating. Even with certified coins no two are exactly alike in any grade. When you decide to purchase one because you like how it looks online, you need to check to make sure what you paid for is what you get. 

Once delivered, look closely with a magnifying glass or jeweler's loop at the coin, and closely compare any minor defects, bag nicks or marks, with the picture of the coin in the advertisement. Like a finger print, no two will be the same. Make sure the picture and the coin are identical.

This advice is doubly important when buying un-certified "raw" coins. While these coins are not usually numismatic investment quality, the difference in looks matters - especially if you ever consider sending a coin in to one of those services to have it certified.

As for eBay sellers, they covet their 'good' ratings from purchasers and will go out of their way to make you happy. At least that has been my experience.

Read all the advertisement. Often they have several coins for sale and should print a disclaimer stating that the coin pictured is a stock photo etc. So always read all they have to say about your potential purchase.

NEVER TAKE MY INVESTMENT ADVICE! 
Consult the professionals