Hi spkimball,
Latex mattresses at that price (which is a low budget mattress using any material much less latex) is unlikely to be available locally and would also be outside the range of even a latex/polyfoam hybrid mattress available online. Unfortunately your budget is too low for the type of mattress you are looking for.
Some of the better options or possibilities I’m aware of in your area are listed in post #4 here.
Post #1 here has all the basic information, steps and guidelines that can help you make the best possible mattress choices including links to some of the better online mattress sources (including latex) that I’m aware of if you decide to go in that direction.
Phoenix