I have seen them in liberty market, lahore near khussa mahal.
Also if you think liberty is too expensive and can brave the dirty dusty jam packed roads of Shahlimi, then you can also find those there. The liberty market store owners buy all their stuff in Shahlimi and they pick out the best stuff, but then they triple the price when they sell it in their own shops .
You can find these kind of bangles anywhere in pakistan. I bought all of mine in a smaller city as compared to lahore. Got the same nice stuff but much cheaper.