What can happen if I rented some things 3 years ago from a rental place and I was down to about owing $1,000 and fell behind?

This would be treated as a civil matter. Breech of your contract is not a criminal matter. If you have been contacted by mail or telephone or on the doorstep by someone saying you are going to be arrested or they are going to get a warrant on you, that is most likely a bottom feeding muck churning third tier collector outfit using tactics that hang over the edge of the line or cross the line of permissible conduct. If someone left a message with a generic though ominous statement about papers being filed at the courthouse, well, sure, papers are filed at courthouses every day. Most likely they let your brain add in the thought that you specifically had papers filed today (which is not what they say.) For what it is worth, most people do not beat around the bush if they are filing a suit. They either day it outright, or they do not say it in advance. If you had a contract originally, it is not too late for you to be sued by the original creditor or someone who has bought up the debt. But the notion of being arrested or going to prison, that's puffery. If you would care to discuss this further, many counsel, including myself, will provide a free initial consultation.