who knows where i can find a good mattress cheap. even a stratch an dent one will work if its a good buy. i live in md but i dont mind traveling if its worth it . the lasat mattress i bought was for 100 bucks  from sticks n stuff it was a 1500 dollar mattress it was well worth thev drive for me to go get it. its time for me to get  a new mattress but there no longer around

You don't mention how long ago you bought a mattress for $100. I've seen some advertised for about $200 to $300 at mattress warehouses, but I would not vouch for their "qulaity." How do you define quality?  If you are really interested in "quality" in the way that most people on this forum are writing about, then the chances of finding something in that low price range are, unfortunately, very unlikely. If you want something that will last for not a long time, you can probably get away with it, so long as you steer away from the "pillowtops" or other mattresses overstuffed with foam that breaks down rapidly. At least, that's what I've picked up after reading this forum for several months now. Others may have some more insight to offer.

Depending on where you live, craigslist may be your best bet for finding a mattress at "give away" prices.

Agree with Craigslist. There's a  wholesaler near me selling "FACTORY DEMOS,SMALL FLAWS, SHOWROOM SAMPLES, END OF LINE AND DISCONTINUED MODELS", some for as little as a couple hundred dollars for a full size.

Craigslist is the way to go.  I had a lot of difficulty selling a mattress on Craigslist a couple of years ago, so I had to drop the price significantly.  It was still a great mattress, but someone got to buy it for very cheap.  You can definitely find some steals on Craigslist.

Personally, I would rather buy a used bed from a clearance store selling used customer "comfort returns" rather than craigslist.  There are two main advantages:  1) the beds that were returned by customers were only used for a few weeks, not for years as the craigslist beds might have been; and 2) law usually requires the used beds being sold by a retailer to have been heat sanitized (you can check on this for your state).  Heat sanitizing kills bacteria and BED BUGS.  I would be leary of a craigslist bed, given how prevalent bed bugs have become. 

I wouldn't buy a used mattress (or anything else with fabric - too afraid of fleas, bedbugs and who knows what else in it?) from a private party, only from a dealer.