Word for money given before a job is started [closed]

"Upfront" is the word I most commonly see used for this. You can use "upfront payment" if you're looking for a noun.

Upfront: paid or obtained in advance

Cambridge Dictionary

As in:

So the tutor asks for $50 upfront and the remaining $50 upon completion.

Or:

So the tutor asks for an upfront payment of $50 and the remaining $50 to be paid upon completion.

This is a bit informal and may seem somewhat out of place in a contract or formal agreement, for example. In such cases I would probably expect to see something like "initial payment" or the details of when it should be paid written out without any single word or term used to describe it (e.g. "$50 to be paid prior to the commencement of the service").

Such a payment made in advance of an anticipated complete transaction is often termed an advance

Advance = money paid before something happens

Cambridge dictionary

The term has slightly less formal contractual overtones than the equally useful and very similar

Deposit = to pay someone an amount of money when you make an agreement with that person to pay for or buy something, that either will be returned to you later, if the agreed arrangement is kept, or that forms part of the total payment

Cambridge dictionary

Would you please transfer $50 to my account, as a prepayment?

or

A 50% prepayment is required for this service.

• prepay - "to pay for (something) before you receive or use it : to pay (something) before you are required to pay it."

• prepayment also pre-payment - "the act of paying for something before you receive it, or the amount of the payment" "Send your order with pre-payment by cheque".

Certain establishments (hotels, travel agencies, hospitals, car rentals) would require a deposit, which is slightly different from prepayment.

• deposit A deposit is a sum of money which you pay when you start renting something. The money is returned to you if you do not damage what you have rented.