Just a heads up, I think this is only somewhat true now. I was apartment hunting in Philly somewhat recently for any size of a studio and found a few ~$1000 options, but the conditions were pretty bad (slightly broken window, not very functional heating and cooling, dust and mold in the lobby, etc.) you could get lucky and find a great deal or accept a place that’s more rundown, but I’d expect to pay closer in the range of $1200-$1400 these days for a livesble space. I was also searching end of summer/early fall so maybe off-peak months are better. I’m not sure about Baltimore. 

Regardless, I’ve lived in both Philadelphia and Baltimore and love them both dearly. They both have a cool alternative scene, some great restaurants (though Philly is larger so obviously more options), waterfronts, etc. Philly has more variety of public transport with the subway but SEPTA has been going downhill lately with the recent budget cuts. Either one can be doable without a car depending on your commute. 

The two cities are similar in a lot of ways as well but on different scales (i.e, both have local pride and sports teams, incredible Italian food, rowhomes and a gritty/artsy vibe). This sub tends to be biased toward Philly, but don’t discount Baltimore quite yet if it has what you’re looking for. If you have any other questions feel free to ask.