When buying DVDs off eBay there are a few things you should consider.
You need to take notice of the Region number of the DVD. Australian DVDs are "Region 4" and a lot of DVD players, especially expensive ones, can only play DVDs that are coded by this region. You need to check what region DVD player yours is before buying any DVDs. "All Region" DVDs can also be played on any DVD player. There are multi-region DVD players available to buy which can play DVDs from any region in the world.
Also, you can purchase codes off eBay to make your DVD player be able to play all regions of DVDs. You just have to check the brand and model number with the seller to make sure thay have the right code for you.
You should take note of whether the DVD is brand new or second-hand. Caution is needed when buying used DVDs as some may be scratched and unable to be played. It is a good idea to contact the seller about the DVD if a there is not a good description of it shown. Second-hand DVDs should be in good condition, have their original case and cover or they are not worth risking buying.
You should always look at the seller's feedback. There are pirated DVDs out there and a person's feedback is a good place to find out if the DVD is genuine or a copy. Buyers will often leave a negative feedback stating their DVD was a copy if they are pirated. Always look at the item description also and check if they have stated that their DVDs are original and not pirated.
Also, you need to be wary of scams. Some sellers have multiple newly released brand new DVDs for sale for very cheap and it can be quite difficult to refrain yourself from quickly buying them. You need to consider whether they are genuine DVDs or if the seller is going to rip you off. It would very very unlikely that a seller could aquire newly released DVDs for a cheap price.
READ THE LISTING PROPERLY
It is important to read the listing properly to find the region number and condition, but also for the methods of payment and postage costs. If a seller only accepts PayPal and you can only pay by bank deposit, you won't be able to purchase the particular DVD.
Also, if you think the postage costs seem outrageous, take note of whether it is regular postage, or maybe it is express or registered. These methods of postage do cost more. Seller's fees may also be included in the postage cost. If you don't agree with postage costs then you can contact the seller and try to arrange a discount or simply not purchase the DVD.
IF SOMETHING GOES WRONG
If something does go wrong such as your DVD has not arrived given sufficient delivery time, or your DVD turns out to be faulty or not as described, you should always contact the seller before leaving any feedback. Most sellers are happy to fix the problem or inform you of a delay in posting. If there is no reply from the seller, then you have the choice to leave whatever feedback you feel is necessary.
Hopefully this guide has been helpful to you for buying DVDs and I hope you have fun buying and watching them!