I'm flying United from DTW to ORD to SFO. However, I have a 3 hour layover at ORD and, in that time window, there are 2-3 earlier flights that depart to SFO from ORD. If I'm not mistaken, United charges $75 normally to be on the standby list for earlier flights or something like that. Are there any tricks that would allow me to get on one of those earlier connecting flights for free (or a lower fee than $75)?
(Note: I don't need a response about why the standby fee exists.)