In Dutch, there is an idiom iemand een sigaar uit eigen doos geven, which literally means to give someone a cigar from [their] own box. The idiom is used when you offer someone something, but it's really them who are paying for it. The idiom has a negative connotation.
For example, it may be used in politics. Suppose that the government introduces major cuts to some service, then restores a fraction of it and presents it as a gift/improvement. Or suppose an employer increases some particular non-salary benefit to employees, but finances it entirely by reducing employee salaries. Critics may then refer to this as a sigaar uit eigen doos.
Is there a corresponding idiom in English? One online dictionary translates it as something out of one's own pocket, but searching the latter phrase in context does not yield examples where it is used with a meaning similar to the sigaar uit eigen doos.