Is it obligatory for someone who lacks water, or is unable to perform ablution by himself, to purchase water and hire someone to help him perform ablution, or is it permissible for him to perform tayammum?

The question includes two issues:

First: Effort must be exerted to obtain water for every prayer, by purchasing water at the market price if the money is available and there is no other need for it. Otherwise, dry ablution (tayammum (definition)) is forbidden if one is able to purchase it, and the prayer must be repeated.

Second: Whoever cannot perform ablution by himself must hire someone to assist him with it at the market price if he can afford it. Otherwise, he prays according to his condition. We know of no disagreement regarding this.