Awwbooboo has written a useful guide CD Buying On eBay that lists important factors that you should consider before bidding for CDs on eBay. I'd like to add a few pointers based on my experience (more than 100 CDs purchased on Ebay) that eBayers might find useful (with awwbooboo's original points in italics.)
1. Check that the CD you are purchasing is 100% genuine. If you don't recognise the title or description given for the CD do a search on Google. Genuine CDs will be listed on many web sites.
2. Check that the sellers feedback is of the majority positive so that you can be ensured a good service. Yes! I have had bad transactions with 3 sellers (CD failed to arrive, seller de-registered) , 2 of these had previous negative feedback that I failed to pick up on. I should have been more wary.
3. Only purchase CD's which have a picture listed of the product to see exactly what you are buying. I will buy CDs that are not illustrated if the description includes some alternative information such as track listing, record label or EAN number.
4. Only buy CD's in perfect condition, you can never be sure the disk will read on your CD player if scratches are visible on the disk even if the CD played fine on the sellers. Check the seller's description of the condition of the CD. If the condition isn't described you can always ask the seller. Minor surface scratches almost never prevent perfect playing.
5. Ensure that the CD you are purchasing is the exact one you want, the seller may not accept refunds for products purchased. Avoid this by avoiding instant/last minute bidding. Things to look out for include original versus remastered CDs (the latter may include bonus tracks not present on the original version) and "promo" CDs that may have fewer tracks and minimal artwork.
6. Make sure the seller accepts your preferred payment method or a method which you can pay by. Remember too that if the seller does not accept PayPal you will incur the costs of sending him/her your cheque/postal order. I bid a little lower on items where this is the case. Never send cash!
7. Ensure that the postage is not over priced eg. You See Buy a CD 99p Buy it Now with postage of £10.00. Quite a few sellers sell in this way. Look at the total price bid+postage when deciding what to bid. I don't bid where postage for 1 CD is more than £2 (unless the item is genuinely rare...). Sellers take note: high postage rates are a turn-off. I am grateful to mandakins888 for pointing out that overcharging for postage to compensate for a low bid price is against eBay rules and if discovered should be reported through eBay's standard reporting process (under 'Circumvention of eBay fees'; 'Excessive postage and packaging').
8. Ensure the seller is situated in a country you feel secure dealing with, eg. You may only feel secure dealing in the UK due to customs abroad etc. Sound advice.
I'd like to add
9. Don't pay over the odds. What is the point of paying more for a CD on eBay than it would cost elsewhere? Ignore the "rare" item description - it's often just a sales tactic - and don't get carried away in the bidding process. I am not going to use an eBay guide to point out eBay's competitors but obviously there are plenty of high street and Internet shops selling CDs! Many of these advertise CD availability and prices online so it easy to check the "going rate". You can also use Ebay's search with the "completed listings" check box ticked to see if the CD you are after has been sold recently and the price it went for. Use this information to judge what is a fair price and then decide what you are prepared to pay. Enter this amount as your maximum bid, and don't bid again if you are out bid. CDs are not unique items - if the price is too high, bid on the next to come along or buy elsewhere.