Moving to Chicago with entry-level salary from Philly, any advice on what area is best/affordable?

This sorta depends on what you're looking for. I'm not on an entry-level salary right now, but I am a little on the broke side, but I'd still avoid a lot of areas on the South Side. Simply put, I'm a white boy from the suburbs and I wouldn't be the best at navigating those areas. You might try checking out some Northern suburbs that are a bit further from the heart of the city. You can find a bus or train nearby to take you most places, but it depends on where you're working. If you work in The Loop, you can get there from pretty much anywhere.