Help guys I can't understant what's the difference between I'd rather present perfect and I'd rather past perfect. For example: I'd rather have spent this money on the holiday (money wasn't spent on the holiday) = we regret or smth... AND I'd rather you hadn't rung me at work (suggests that he/she did this call then why I can't use present perfect?)
I think your example "I'd rather have spent this money on the holiday" is a shortened version of "I'd rather I'd have spent this money on the holiday", in which case the tense following "rather" is expressed by the "(woul)d" and what follows, "have spent this money", is non-finite, meaning there is no tense in "have spent this money". It is logically a past tense, but a perfect form is the regular replacement in English for a past tense in a non-finite context. Compare "It's not possible that she ate clams" = "She can't have eaten clams".
In your second example, "I'd rather you hadn't rung me at work", the morphological past expresses something contrary to fact -- a sort of subjunctive -- rather than a real past tense. Compare "I'd rather you didn't ring me at work", where the sense of "did" is future.
The construction of a sentence with "rather" depends on whether the subjects of the two clauses are the same or different. If the subjects are the same, the verb takes the present form, whereas if the subjects are different, or the subject is restated, then the simple past is used. For example, compare:
I'd rather leave.
I'd rather you left.
Now in the case of a predicate in the perfect tense/aspect, such as "have spent this money on the holiday," have is the verb to which this tense change will apply, so you could say
I'd rather have spent this money on the holiday.
I'd rather you had spent this money on the holiday.
Similarly, you could switch your second sentence around, so if you had rung the person you are addressing, you might say
I'd rather not have rung you at work.
Or you could restate the subject (I), and make it
I'd rather I hadn't rung you at work.