I know a lot of cab companies do a standard fair of $26.25 to get into Center City, not sure what the difference would be for South Philly. You can try to get a good idea of it here:
Taxi Fare Finder Philadelphia - Estimate Your Taxi Cab Fare and Rates
Also, if you're public transportation savvy, you could consider taking the R1 train to Suburban Station, and switching to the Broad St subway line south to Oregon and walking the 4 blocks. You could do that all for the $10 purchase of a one-day pass. (Probably not a good option if you're going to be carting luggage with you).
SEPTA
Hope that helps!
