Learn Italian: Se il consulente facesse il suo lavoro, risparmierei molti soldi. - If the consultant did his job, I would save a lot of money.

Verbs like fare, dire, and bere use their old, longer Latin stems to form the imperfect subjunctive. For fare, the stem is fac- (just like you see in the imperfect indicative facevo). You then add the regular second-conjugation endings, which makes it facesse for the third person singular.

Why do we use the imperfect subjunctive (facesse) after se instead of the present tense?

This sentence describes a hypothetical or unlikely situation in the present or future, meaning the consultant is not actually doing his job right now. When using se (if) to talk about imaginary situations, Italian requires the imperfect subjunctive.

Why is the verb risparmierei in the conditional tense?

This is the second half of a hypothetical "if" sentence. While the condition part uses se plus the imperfect subjunctive (facesse), the result part (I would save) always takes the conditional tense (risparmierei).

Why is it molti soldi? Isn't "money" a singular word?