Q. Can I buy a used car during the 3 weeks?

A. See Ask the Rabbi (this forum, question 100), for the permitted buying of a new car when possession will take place after Tisha B’av. As this is a used automobile, ownership would be immediate. Mikdash Isroel, (Bein Hametzorim 7, p. 17), permits buying a used car, especially if its primary use is for work.

Horav Shlomo Miller’s Shlit”a opinion is that since this car will presumably be used by other members of the family too, the correct brocho to be recited would be Hatov Vehameitiv, (as more than the buyer will benefit from it) and not Shechecheyanu, (see Igrois Moishe O.C. 3, 80), and therefore it could be purchased if needed immediately.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a.