To start, it goes without saying that this shaving hobby is typically not a money-saver, even if it's pushed as such by enthusiasts trying to convert people to this style of shaving. Looking at the price of shaving soap using price per oz. is fairly common (I still do that sort of thing even when I'm in the grocery store), but die-hard hobbyists tend to scoff at it, because, well, you sometimes get what you pay for.
With that being said, there are people all over the world with varying budgets, and like any hobby you can spend as little or as much as you want. From Col. Conk to Sebum Gold, there's a wide spectrum of cost for shaving soap.
In this recent video from Stirling Soap Company, Rod talks about how tubs are the most cost effective form factor. Samples and even Refill Pucks are more labor intensive, making them more expensive per oz. You might assume, as I did, that a refill puck would be cheaper per oz. because it doesn't come with a plastic jar, but you would be wrong.
But wait! Take a look at Barrister & Mann. They recently lowered the cost of their samples to $3.99USD, and their samples are a full 1 oz., just like Stirling. That makes them $0.11USD cheaper than Stirling samples.
Now lets do some math.
5.8 Stirling samples to make one of their shaving soap jars: $4.10*5.8 = $23.78, a lot more expensive than just buying a jar for $14.24USD.
4 B&M samples to make one of their shaving soap jars: $3.99*4 = $15.96, a whopping $9 cheaper than buying a tub for $24.99!
Does a tub, label, etc. cost $9 extra? Are the samples a loss leader like rotisserie chicken and hot dogs?
Either way, it's great to have both of those companies offering generous samples. House of Mammoth also has relatively large samples, but they're 1/2oz for $6.00USD.
As a wetshaver from the EU, I can give another view regarding samples: You can consider yourself lucky that in this hobby, where most top-notch artisans are US-based, they often offer samples. Over here in Europe, almost every soap tub is a blind buy, just judging by scent notes and other wetshavers' reviews - unless it's a european artisan like E&S Rasage, who offer nice little samples of their soaps and aftershaves. But unfortunately, "try before you buy" is simply not happening over here in most instances. If you want to buy samples, a british or american vendor is your best choice and even then you might end up paying a lot more than you hoped for thanks to duty fees.
Perfume or the fragrance community in general is comparable to our hobby, but there you have the luxury of trying out scents in brick and mortar stores or getting 2 ml sample spray bottles. A lot of scents are just expensive for the luxury factor and the brand name, others are more fairly priced but it's still "you get what you pay for". I don't expect extreme longevity from a 20€ perfume, but one for 150€ should better have some staying power to justify that price tag. I think a lot of this goes for every hobby: well established brand names can charge more than newcomers, popular brands often cater to a more mainstream audience, there are some "hidden gems" here and there and also some things were the hype was simply unjustified.
But overall, I sincerely agree with your take that this hobby won't save any money. Sure, if you do it like my grandpa's generation and just always use the same soap until it's empty, just own one razor where you only need to replace the blades and use only one brush until the bristles fall apart - then it's a money saver. But despite our best efforts to comfort ourselves with that "traditional" wetshaving will save so much money, it won't when you get seriously crazy into this hobby. I openly admit that one year I spent close to 700€ in soaps, aftershaves and razors and it's something I'm definitely not proud of...
700 currencies is a hefty sum, but I compare it to other hobbies and all of a sudden it's a bargain. A single styrofoam RC Airplane costs about $2-400USD. Buy a couple of those plus a $400 transmitter, some batteries, and a charger... It adds up but it's fun.
Yeah, wetshaving is definitely not the most expensive hobby. The "entry fee" (so to say) isn't that high compared to others - Photography is very expensive to get into, for example. Golf is a sport for rich people and you realise why when you see the prizes for the equipment and memberships. A lot of hobbies are, simply put, a luxury. You get what you pay for and quality has its price. But that one spending spree was kinda a wake up call for me - never did I want to go so crazy again, most of all since a lot of stuff was just for LG and I didn't even really enjoy it.