Check with your local legal aid organization. There were far more attorneys willing to do pro bono bankruptcy before the 2005 bankruptcy laws went into effect because there is so much more work required now.
It may be that you have a very simple bankruptcy and it can be done easily. You can request the fees to be waived. A paralegal can prepare the documents for you at a very reduced cost. e-mail me and I can see what we can do. firstname.lastname@example.org
I dont agree with my collegue about using a paralegal. I have found that these petition preparers do not know what they are doing half of the time. If you are going to use one you need to do your research. I would check with your local legal aid before anything.
You may want to consider an alternative to Bankruptcy, as the amount of $20,000 may not justify your filing bankruptcy, since you have no wages that they can garnish, and (for sake of this discussion and few facts) not much in your bank account and no real estate on which a lien may be placed.
Below is a link to my web site which explains alternatives, even if you were to be sued by a debt collector or creditor. My thought is to send a letter to each of the creditors or the current debt collectors and tell them you have lost your job and with the down economy in the Modesto area, it may be a long time before you find another job, and that you have no assets with which to pay the debt. Send that to each creditor at their address for correspondence (not the payment address) and each debt collector. Regular mail is fine, but keep a photocopy of each letter and date each letter. Sample letters are on my web site as a template, but I would not send any of the dispute letters at this time, just your financial status and that you are considering filing bankruptcy. Do NOT offer to pay anything or promise to pay later, since you really do not know.
My hunch is that this may help you avoid being sued for a long time, as these companies don't want to pay the filing fees ($200 or more per case) and attorney's fees (perhaps $500 or more per case), only to have you file bankruptcy and they get nothing anyway. If they don't sue you and wait beyond the statute of limitations (two, three, or four years), then they cannot sue you after that, if there are no payments from you. If you have questions about this strategy, please feel free to call me through my Avvo profile for a consultation.