Sellers are getting really clever about copies now - generally now the only way to tell is by the dustbags and the tags.
SPOTTING A FAKE WHEN IT LOOKS REAL
So, first off.
Louis Vuitton bags NEVER have tags attached. This is because when you go into a store, all the bags are behind the counter. The only tag-like item that comes is a small piece of card that says the bag is cowhide. There is nothing attached.
Why would someone sell a brand new bag for a starting price of 99p? If they don't give any reasons, that generally means it's not genuine.
Quite a few number of the bags in the LV range don't have a little leather square saying 'Louis Vuitton made in Paris' inside them. This includes the small pochette bags, Noe and petit noe etc, neverfull (however one does have the logo as part of the lining). I should know, I have them.
Dustbags. Yes, these can tell you a lot about whether the bag is real or not. Now I don't know much about ones pre-2006, but if an iterm is claiming to be new or nearly new, check the dustbgs. It should look made of soft, thick cotton, be that yellowy LV color and only say 'LOUIS VUITTON' on it. No LV logo. No 'Fondée Paris' crap. Just Louis Vuitton.
Seriously, lots of sellers have convincing looking bags. Just make sure you look for these little giveaways.
Good luck everyone!!