Hi timberghost,
In case you haven’t read it already … post #1 here is the best place to start your research and has all the basic information, steps, and guidelines that can help you make good choices.
Some of the better options I’m aware of in the Los Angeles region are listed in post #2 here.
The Insight has just under 3" of 4 lb gel memory foam over a firmer polyfoam core and there are many memory foam mattresses that have this basic construction (although different types of memory foam and different firmness levels of polyfoam will change how they feel compared to the Insight). You are on the low end of the budget range for a reasonable quality memory foam mattress but you should still be able to find a basic model available locally and if not you also have some good online choices available in your budget range.
Phoenix