Is it permissible to buy a few kilograms of meat and distribute them among the poor to earn the reward of Udhiyah, given the inability to slaughter a whole sheep, especially since the salary is entirely spent on household needs?

The Udhiyah (sacrifice) is a confirmed Sunnah, and its virtue is great. It is legislated for the husband to include his family in its reward, and one sheep suffices for a household. Buying meat and giving it as charity does not substitute for the Udhiyah. A woman's money is her own, and she is not obliged to participate in household expenses, as this is the husband's duty.