"It doesn't matter what's the price, you'll buy it if you want to or not."
Not always. Not if you have 600B spending space and 400B of cash. Not everything is worth taking loans for. It'd be nice if total cost and total cash appeared on the page for exactly this reason. Now if you'd like to present a serious argument as to why it is a good idea to make players open another tab (to look up cash), I am all ears, but so far all I have heard from either of you is condescending "get out a calculator" tripe. Not to mention that looking up available cash requires opening up a separate page, which is another request on the server.
"If you are placing an order for it, its obvious that you think you need for whatever you are planning."
Have you ever heard of speculation? Strictly speaking, products that one is speculating on are not NEEDED. Additionally, some orders such as ammo can be postponed for a very long time if a player finds he has spending space but not cash.
"So, if you don't buy it, then what?
We aren't playing Cost of Opportunity. Divert your attention to more important matters."
Actually opportunity cost represents a significant principle of economics, upon which this game is based. Even if not everyone understands the wonky economic theory behind it, most have some sort of vague idea that "if I buy A now, I might not have the cash/might have to take out loans for B later."
"Simcountry gives you the chance to accumulate resources to buy products without the need of a PhD in Finances or, for that matter, a calculator."
The information that the OP is requesting requires the use of a calculator to get under current circumstances.
Now would the vets please stop being condescending pricks. Yes, "doing some math" is the short-term workaround to the OP's suggestion NOT being implemented, but I have yet to see any serious reason from either of you as to why this suggestion SHOULD NOT be implemented, given that it is a relatively simple change that only adds a couple pieces of information to a page, mind you information that is extremely relevant to that page.