For stars, there’s usually, there are up to four payments:
1- an advance payment (sort of a downpayment on the performance)- for example, if the actor is to receive $5 million for the role, they may be given $1 million in advance as “good faith” and to handle their expenses
2- a drawing account, which is basically a weekly salary plus all expenses when shooting on location. (Expenses can include full salary for the actor’s staff or for his/her family to visit.)
3- The “big paycheck”, which is usually paid when production wraps. The drawing account may or may not be deducted from this; it depends on what the actor and his/her agents negotiated.
4- The “back end” deal, which is paid usually quarterly or annually once the movie has been released and gross/profits have been assessed. (The contracts for these can be book length in order to protect the actor against Hollywood’s notoriously famous “creative accounting” practices- for example, Art Buchwald sued the producers of COMING TO AMERICA and won a small percentage of the profits; the movie cost about $35 million to produce, grossed almost $200 million, yet according to accountants never turned a profit, so when an actor receives a share of the profits they are VERY VERY specific about what defines “profit”.
Cary Grant often did roles for a tiny payment up front and a huge share of the gross (for OPERATION PETTICOAT it was 25%, something that probably even Tom Cruise couldn’t get today). Alex Rocco, who played Moe “the guy who got his eye shot out” Green in THE GODFATHER, took the role for about $7,500, BUT because of shooting delays with his scenes he remained on his drawing account the entire time and made more money from that than from his salary. (GODFATHER still came in on schedule and under budget, the last F.F. Coppola film able to say that.)
Bit players, extras, etc., are usually paid weekly or monthly. They receive meals (quite different from what the stars are fed) and expenses if they have to stay on location, but generally it’s pay for play.