Technically, my first designer purchase was a second hand, damaged Charles David bag. It had a small tear on the back side, so the lady sold it to me for $10. Aside from the small tear, it was a very nice leather bag.
That bag inadvertently led to my first designer item purchased (that wasn't second hand) though also. Because not long after, we visited my Mother-in-law, who promptly noticed the tear on the bag while it was sitting on a chair and lit into my poor Husband about why he'd make his wife carry a damaged bag and to get me a new bag. It wasn't my Husband's fault though, I was much more of a cheapskate then and not used to spending on myself for indulgences, even though he has always been more than happy to enable & indulge me. And he finally had the opportunity to make me give in and pick out a new bag. Which was a nice black canvas & leather bag from Juicy Couture. I loved that bag and wore it until the straps fell apart. This was back in our first year of marriage, when Juicy Couture was still a popular mid-range Designer brand... (I still haven't convinced myself to take a plunge on my "real" designer wants... Which mostly are McQueen bags.)