Welcome to EL&U! This might better fit the English Language Learners StackExchange. To answer your question, I suggest you look up the concept of a "double object." For the verb buy here, "the boss" is the indirect object and "a new Porsche" is the direct object. In this construction, a preposition is not required.
– TaliesinMerlinSep 21 '20 at 17:41
Some verbs undergo the dative shift (He bought a cycle for me ⇔ He bought me a cycle) while some don't (He acquired a cycle for me ⇔ *He acquired me a cycle). Note that 'for' is dropped in for instance 'and buy the boss a new Porsche'.
– Edwin AshworthSep 21 '20 at 19:03
You could optionally add to to make it ...and to buy the boss a new Porsche.
– DavoSep 21 '20 at 19:13
Thank you a lot @TaliesinMerlin, today I learn the "double object verbs" grammar. Thank you a lot.
– Luan PhamSep 22 '20 at 03:03
@JohnLawler I've expected the "for", so the sentence should be "...and buy for the boss a new Porsche"
– Luan PhamSep 22 '20 at 03:03
@LuanPham The for marks a benefactive construction, not a dative (indirect object), which uses to exclusively, when it uses a preposition at all. The original clause would be (they) buy a Porsche for the boss. The reverse order buy for the boss a Porsche is ungrammatical. [Only* in case the boss winds up owning the Porsche](https://english.stackexchange.com/a/90534/15299) can the clause undergo the Dative alternation, and produce buy the boss a Porsche. If you take a bullet for the boss, you can't say *take the boss a bullet.
– John LawlerSep 22 '20 at 14:00