Forget the 'expert' advice! The best reason to buy a piece of art is because you like it.
There are all kinds of artwork on eBay, by everyone from Victorian professionals to modern amateurs. Some people will tell you that you should only buy a painting if its value is expected to consistently climb. Others will tell you that you should buy art that has fallen in price, because the expectation is that it will rise again faster. The truth is that such opinions are no more scientific than share tips - and look how many people got the wrong investment advice from so called stock market professionals!
My advice is to buy paintings for the best possible reason - simply because you like them! Life is too short to worry about whether a painting might one day, in the distant future, be worth a few pounds/dollars/euros or a few thousand pounds/dollars/euros or a few million pounds/dollars/euros. Whichever the outcome, it will take some considerable time to appreciate in value and it is far more important to be able to enjoy looking at an artwork, rather than having to look at something you actually don't like, which is stuck in your home and makes you wonder if you made the right choice.
The chances of finding some really valuable artwork on eBay are virtually zero! So forget the advice of self appointed art experts and enjoy your painting - that's the real reason the artist painted it!
Happy art buying!