Depending on what your selling always add this to your listings especially if its an expensive or electronic item..
I DO NOT POST TO NIGERIA OR ANY OTHER COUNTRY, I AM AWARE OF SCAMMERS..I POST TO UK ONLY
Put that in your listing somewhere and that will save you a lot of time and hassle later on down the road..
I have nearly 100 feedback on ebay and have bought and sold on there since 1999 so I know what I am talkng about, listen to the rest of the advice dolled out on here as its very good advice..
As for Paypal it is convenient but they do take a 4.5% commission from all sales that go through them..Other than that its a postal order and if they do it this way make sure you stipulate that its not crossed as otherwise it will take time to clear in your bank account..Cheque will take 3-5 working days to clear so again don't send the goods until the cheque is cleared and the money is in your account..
On the subject of Bank transfers I would say stay clear if you don't have much experience on ebay, there are plenty of scammers about and all they need is your account number to do serious damage..But at the end of the day its your account so feel free to ignore me if you want..
eBay can be a great place to get rid of unwanted items, Always give a good description and don't lie about the items condition or it might just come back and bite you on the bum..If it works say it works, if it don't then say so..You then have nothing to hide and the buyer will thank you for it..
Good luck any more advice you can PM me..