I find The-Numbers to be the best source for budget/box office online. Here's their listing
for Mars Attacks!
Budget: $80 million
Box office (US): $37.77 million
Box office (foreign): 63.6 million
Total box office: $101.37 million
I'm sure it broke even on television and home video, but at the box office it was surely a flop (remember that those are box office grosses; the distributor/studio doesn't get all of that money back, and they don't list the cost of advertising as part of the budget).