Usually the community is only allowed to offer their sacrifice of Eid after the imam of the Eid prayer has offered his sacrifice.
My question is if the imam was unable to afford the price of a sheep is it still necessary that he offers the first sacrifice and if so can he offer a sheep in place of somebody else? (If you could explain the views if different fiqh schools that would be great)
According to al-Jaziri, if the Imam does not offer a sacrifice, then the sacrifice may be made by the common people after an interval of time has passed in which it would have been possible for the Imam to have made the sacrifice. This would be the case if the Imam is not able to afford it.
المالكية قالوا: يبتدئ وقت الأضحية لغير الإمام في اليوم الأول بعد تمام ذبح الإمام. ويبتدئ وقتها للإمام بعد الفراغ من خطبته بعد صلاة العيد، أو مضي زمن قدر ذبح الإمام أضحيته إن لم يذبح الإمام
According to the Malikis, the time for slaughtering one's udhiyah for people other than the imam begins on the Day of Sacrifice after the imam has slaughtered his. The time for doing so for the imam himself begins after he has completed his sermon following the holiday prayer, or after sufficient time for the imam to have slaughtered his udhiyah has passed if he does not, in fact, slaughter an udhiyah.
As far as I can tell this condition regarding the starting time for sacrifice exists in the Maliki madhab. The others generally hold the view that the time begins after Eid prayer, see for example the view of the other madhabs in the reference above and in الفقه الإسلامي وأدلته and الموسوعة الفقهية and islamweb.
