30000 down on a home under 100000K. Assuming income is OK how good does my credit need to be

You may if you can find a lender willing to accept your credit scores - there are a few. Your interest rate will be higher than less risky borrowers and whatever issues caused your score to go down might also need to be addressed or may cause your application to be declined. It may take some time but keep trying - get a solid mortgage loan pre-approval prior to making any offers - i hope you'll be enjoying your new home soon!