As far as the value of a hammer it depends upon your wants, needs, and pocket. Being new to this hobby, I don't have enough time or energy left at my age for this to be considered a hobby by me, I can relate this question to my flintlock experience. I have assembled a few in my time out of purchased parts. I used to spend about $400 for the main parts.
I remember going to a reenactment rendezvous some years ago. Back then you could by a "factory made" flintlock for about $4 to $600 dollars. Semi customs went for around $1200. I came to the display of a well known gunsmith, he had a rifle on display for sale. The price was $20,000! I had to ask why so much? He graciously took the time to explain to me why. He had meticulously kept a record of the time he spent making this rifle over the course of a year. He had never done this before and was curious himself as to how much time it took him. When he added up his hours and multiplied by an average hourly wage for a craftsman of his caliber, he realized $20,000 was under valued. This man made the entire gun by hand. He hand forged everything barrel, lock, butt plate, trigger, trigger guard. He also bored and rifled the barrel by hand. The man even made his own tools. This rifle would only increase in value over time, while factory made, and semi custom rifles would depreciate. I bought my hammers from HF for about $9 each. Do they work, yes. Will they be as comfortable to use as a $140 hammer, I doubt it, but for my needs and pocket capabilities they are just fine. When my family disposes of them they will probably be worth about $3 each. So are $140 hammers worth it? Like everything else in life, depends on your wants, needs, and pocket. Years ago I would scoff at a hammer that cost so much, as I worked for a living and had a family to support. Many years later I have come to understand that there reasons for everything, some reasons are better then others.