I am interested in purchasing a condo with 3-5% down or even better 100% financing...?

I have imperfect credit (score of 650) but a co-signer with excellent credit...Is this possible? I am a first-time home buyer and the price for the condo is $115,000 in NJ. Would it be a better option to have my co-signer listed a primary for a better rate? I am trying to get an understanding of how things work and would like some guidance. In addition to that, my co-signer owns their home outright...is that a bonus for me? Please help me with any guidance possible. One more question is it possible to get a co-op loan with the same options? Please help. Thanks : )