"для / на одного человека" — When to use "на" or "для", respectively, in the sense of "for"?

Question

It seems to me that in some cases the preposition на is used in the sense of for where I would use для. In the following two examples I would use the preposition для, but apparently this is only true for the former example.

Сколько стоит комата для одного человека?
У Вас есть комната на одного человека?

According to this website, на — in the sense of for — is only used for a temporal application or for a deadline (which is temporal use once again).
I didn't find any other sources that address на related to the subject in matter. Most sites discuss the matter 'location', e.g. in/at a factory, at a meeting, on an island etc.

So, when to use на and is there a rule (or rule of thumb) when to use на over для?

Answer 1

На with Accusative Shows a quantitative measure of something указывает количественную меру чего-либо

Товару на сто рублей. ◆ Аренда на два года. ◆ Рыба тянет на три кило. Комната на одного человека.--A room (meant )for one person (describing the room ) Комната для одного человека (describing the purpose I want to live alone in this room ).

Answer 2

You can use the both variants, but the first one is ambiguous.

Сколько стоит комната для одного человека?

• This can mean "How much is the room for a certain man (whom I know)?" Because the word for "one" can be used in a sense similar to "one friend of me", "one colleague of me", in place of "certain". So this may be understood as

How much is the room for one important man?

• Another meaning this phrase can have is "How much is the room which is intended for one person?" Implying that you maybe want to live there in greater number, you just want a room that is designed for one man.

• Third meaning this phrase can have is that it implies that the same room costs differently for one person and for several ones. So you are asking "How much is this room for a sole man as opposed to several payers". Even if they do not intend to live there the room may cost more or less if you are together as a group. This may imply "Sorry, I am not alone in this hotel today, but what if I were alone, would it be cheaper?"

On the other hand,

Сколько стоит комната на одного человека?

Does not have such ambiguity. It clearly means you are asking how much is this room for one person to occupy.

Сколько стоит комната для одного человека?

in this sense looks like a calque from English to me.