The purpose of this study was to examine the impact on learning, attitudes, and costs in a redesigned general education undergraduate biology course that implemented web-based virtual labs (VLs) to replace traditional physical labs (PLs). Over an academic year, two new modes of VL instruction were compared to the traditional PL offering: (1) all VL with an in-person help center (VL-A) and (2) a hybrid flipped VL model where online labs alternated with in-person labs every week (VL-H). All three lab types included a face-to-face lecture with the same materials. Engaging inquiry-based exercises were developed for each VL activity in which students were provided background information, guided through a series of basic experiments, encouraged to design their own experiments, and required to produce a simple scientific report that was delivered for evaluation electronically. The VL-A group had the highest proportion of repeatable grades (below a C, 2.0 grade points). Students in the VL-H group achieved significantly better grades compared to the other lab instruction groups. The VL-H group also experienced statistically significant favorable shifts in their self-reported attitudes towards biology. The personnel costs for the VL-A and VL-H models were 29% and 63% of the PL model, respectively, allowing more sections to be offered. These results suggest that carefully designed online lab opportunities can result in higher student grades and more favorable attitudes towards science while reducing costs compared to traditional labs.