Well Mario was pretty much worth the Pens franchise.
Let's say Mario was not injured/didn't get cancer. And it was 1991/1992 around the time Lindros got traded. Take the package NY offered Quebec.... Kovalev and so on... and add $25-30 million in cash.
Depending on when he got traded Mario's value would have been greater in $$$$ terms. When cash was allowed in trades. You could never have traded him for just players because it would have so fleeced a team they wouldn't be able to compete at all.
In terms of Salary... in 2001-2003... before the lockout when salaries were at their peak. If Gretzky or Mario were 25 or 26 or 27 years old and UFA some team would have given them an ARod type of deal... $25 million a year for 7-10 years.