carlos is hoping to save at least $200 in the next four weeks. his mom gives him $30 each saturday
Carlos will receive $30 every Saturday for the next four weeks.
In total, Carlos will receive $30 x 4 = $<<30*4=120>>120.
Therefore, Carlos still needs to save $200 - $120 = $<<200-120=80>>80 more. Answer: \boxed{80}.