We traveled in Italy several years ago and fell in love with balsamic vinegar. It was usually thicker, almost syrupy compared to the usual balsamic vinegar found in grocery stores here. I hunted around a bit, and discovered the super pricy ones - like you said $150+ for a small bottle, depending on how many decades it had been aged. Those really tasted great! But then I read a tip in somewhere which said to buy an inexpensive balsamic vinegar and boil it down to about 2/3rd of the original volume. You could boil it down some more if you like a thicker consistency, or more robust flavor. That tip worked well for many years.
We just ran out of a small bottle of balsamic which we had bought for $40 off woot - it was very tasty and we enjoyed many caprese salads with it. But I will be trying the boiling down method again. The flavor and price were both right. However, you won't get bragging rights because you won't have a fancy, expensive balsamic in your pantry.
It worked for me, YMMV.