Mario Lopez is weighing in after his Saved by the Bell costar Tiffani Thiessen‘s claims about their virtually nonexistent residual checks. Thiessen, 52, recently alleged that her residuals for the NBC show, which ran from 1989 to 1993, had “dried up.” “It’s like, negative now,” she told Page Six last month. “It costs more to print the check.” Thiessen, who played Kelly, recalled how she “didn’t start making real money” until she joined Beverly Hills 90210 in 1994, adding, “We didn’t have to pull on that show. We made nothing and we just did our job. … When we went to primet...