Is it permissible to sell projects in such a way that a person takes a project in his name from an establishment at a certain price, then gives it to another contractor to complete it at a lower price?

It is permissible to sell projects and to hire others to perform work that has been contracted for, provided that the contract does not stipulate that the contractor must perform the work himself, and that he does not sell the project to another. It is permissible for someone who has leased something to lease it to another for the same amount he leased it for, or for more or less, unless the lessor stipulates otherwise. As an example of this, a company contracted to clean mosques may hire workers for less than what was agreed upon, unless the purpose differs for the lessee, as in the case of hiring a scribe for a book. If the lessee desires the copying to be done by a specific person due to his handwriting and quality of work, then this person is not permitted to hire someone else to perform the work for which he was hired.