It depends. If we're talking SAG (Screen Actors Guild) minimum rates, a principal performer on a modified low budget film (total budget under $500,000) is only $248/day or $864/week. (Appropriate that actors charge for a three-day week (close enough), just like the cameras and lights.) On a feature with a budget over $2,000,000, the SAG minimums are $655/day and $2,272.
Of course there's no guarantee that the actor you're negotiating with will work for the minimum, but at least that's what the minimum is. (There's also "SAG Experimental" which is even cheaper, but I usually advise people to avoid that if they have any intent on making a commercial product.)
On a non-SAG film, it can be anything, down to "100% deferral" (which usually means you get nothing...ever). On SAG films they have limits on hours and days worked and rules about overtime. On non-SAG films, you should be used to working 10-14 hours at a stretch and expect to work 6-day weeks.
(I don't guarantee that these are the latest rates; double-check the latest SAG contracts before figuring your budget.)