Hi,
I have no issues with second hand clothes for a newborn, if people are anything like me: we had that many baby clothes they were hardy worn before the DD's had grew out of them.

I'd invest in a few good quality jumpsuits(Bonds, Target or PP are my favs), bubs are usually more comfortable and also more user friendly for parents.

Ebay is great for bargains, depends on what you are after though. Second hand designer clothes can often sell for as much as they are new!

Good Luck!