I would recommend that you start with Housing Counseling that is available at no cost through one of Philadelphia's Housing Counseling Agencies. They will help you determine if you are ready to buy. They also have some Grant Money available.
Go to http://www.phila.gov/ohcd/cslgagencies.htm
to find the office that is near you.
Good luck in your endeavors,
Kem Bailey Smith
Keller Williams Main Line Realty
Residential Mortgage Loan Officer
Jason R. Knee
6000 Atrium Way
Mt. Laurel, NJ 08054
Numerous lenders now have a cutoff at a 620 credit score. If you fall below this 620 score there will not be any options for standand mortgage financing. However, if you are above this score and do not have substantial outstanding collection/judegment accounts there may be something you could do.
Do you know what your credit score actually is?