Unfortunately yes it's always been this way.
You used to get the cost of the vendor as it's starting pay and back then the gold would go a lot further. But back then you weren't placing vendors and putting things worth hundreds of thousands or millions for sale so it actually lasted a lot longer.
I forgot to say since you're a new vendor owner you may misunderstand. Place the bod in the empty bod book. Price it for however much. When you place it on the vendor hit your ESC/escape key and the book itself will be priced as not for sale. Then you'll be able to open the book and buy the bod.
Also, most people tend not to bother with opening up lots of bags, so using the main pack of the vendor is always your best bet. But if you want to place a bag or box as not for sale and set a description, simply type a comma and the descriptive words after you place the box or bag.
IE: , REFINEMENT COMPONENTS
This will tag the bag as "not for sale" and the line beneath will read "REFINEMENT COMPONENTS"
If you want to leave the bag with no description just hit the escape key after placing the box/bag. You can also place key rings as not for sale on vendors. All other items must be priced.
Double check your bags. If an error happens and you priced all the stuff in your bag but didn't make sure your bag was "not for sale" the bag will default to default vendor price (usually 4gp) and someone will be able to buy the entire bag for 4 gold. This applies to everything you place on your vendor really. Default vendor price is not a good way to make money
Good Luck. If you have any more questions ask away. I am sure there's a few folks who have never placed a vendor that could benefit from your learning curve.