Check Craigslist often and also have a look at goodoldboat.com sometimes boats come up for next to nothing or even free
Just some practical advice....
If you are really on hard times then on-the-water is the last place you want to be with kids - even if you love the "lifestyle." Lifestyle is something to think about when necessity has bean dealt with.
I'm not being judgmental at all - just offering another point of view - As much as I love my boat, if it were not in good shape I would not risk something happening to my family in it - I'd rather be in a camper where the worst that can happen is that I get wet - as opposed to drown.
Best of luck and I hope that the hard times come to an end soon