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?