Is it permissible for one who is in debt and cannot offer a sacrifice to shave his head and clip his nails?

The Udhiyah (definition) (sacrifice) is a confirmed Sunnah (definition) for the one who can afford it, and it does not become obligatory except through a vow (Nathr) or a will (Wasiyah). There is no blame upon the one who cannot afford it, for the Prophet, peace and blessings be upon him, sacrificed on behalf of those among his Ummah who did not sacrifice. There is no harm in trimming hair and nails during the first ten days of Dhul-Hijjah for those who do not intend to offer a sacrifice.