Mattress Forum

So my latex mattress arrives from SleepEZ tomorrow - but I don't have a foundation yet.  I planned to buy one locally, but now not 100% sure on the ones I looked at.  I was looking at wood slat foundations because of cost and someone here recommended one over box springs (for Latex).  Here's what I found:

1. One local manufacturer builds their own and wanted $275 for it (I think he said it's 8 or 9 slats across it total).  I can't detect any give at all - as in, it would be almost like having the mattress sitting on plywood.  Is this okay?  Do I need something with some flex to it?  Or is it okay that it doesn't have any give?  This store recommended box springs, but if I remember correctly, other stores used wood slat foundations.
2. A local furniture store uses all wood slat foundations.  The cost is only $140 for the King size foundation (well, two Twin XLs) with no return policy (except for defects).  I can't tell any difference between this and the $275 locally manufactured one - both have no give to them at all. 

So what do you think?  Should I look for other options or is this what I should expect from a wood slat foundation?  And is it okay to just rely entirely on the latex for the support (9" of latex FYI)?  Thanks,

--Kyle