Just out of interest, Samuel K. Skinner’s testimony before the House Subcommittee on Government Management, Information, and Technology,Committee on Government Reform, May 24, 1999, on why the Presidential Salary should be increased (it was, to apparently twice that for Bush as it had been for Clinton).
The president makes 400,000 US Dollars one year taxable. George W is the first president to be paid at this pay rate. Clinton and the recent previous presidents were paid 200,000. The job also comes with free rent is a spacious home, 24 hour security, and chauffeur service.
Our first President, George Washington made 25,000 USd a year, a tidy sum for 1789.
To answer the other questions: No, there are no bonuses.
Some presidents held jobs early in their careers which paid far higher salaries than they earned as president. Examples would include Herbert Hoover (mining engineer), Ronald Reagan (movie actor), and the current president (oil and baseball executive). But these men didn’t move directly from outside industry to the presidency; they held lower ranking political jobs first. (In the above examples, Hoover was Secretary of Commerce, Reagan was Governor of California, and Bush was Governor of Texas.) So these men took huge pay cuts when they entered politics, but not at the moment they assumed the presidency.