There is a bus called the Attraction Express that runs from Sanford to Universal, but I think it runs on a fairly limited schedule.
You’re going to end up spending as much on transportation as you would on flights to Orlando airport. For example, Mears charges $112 each way for a luxury vehicle.
Taxis will also be standing by; I believe it’s a metered rate.
Uber and Lyft drivers will pick up and drop off there, but there will not be nearly as many of them as at MCO, so you may wait a few minutes for a ride.