Difficult decision - because if you wear them and decide you don't like them, resale on ebay might be hard (unlike with other items) because of the high chance of damage.
Depends how much you're in love with them (and how much cash you have). In an ideal world, check them out in the shop. If anything seems sub-standard, walk away, because this is not a versatile item that'll last for years. But if you're in utter lust, buy them.
When you get home, don't wear them straight away. Let them sit for a few days while you consider if they're really something you'll use a lot. If you've gone off them, sell them on ebay, pristine and unworn, and hopefully get a good price.
And if you like them and keep them, us deprived people want to see pictures!