Buying the bike in the winter should get you a decent deal.
An aluminium bike by Bianchi with shimano 105 on it should be possible.
I am a Campagnolo fan, but I don´t know if you can get a good deal on a Bianchi with campa centaur on it for a 1000 euros.
A well cared for second hand bike is definately interesting if a shop has one that fits you well.
Buying a second hand bike straight from another cyclist is a risk if you dont know what to look for in a bike yet.