Hi jethrodesign,
The Berkeley Ergonomic mattresses are certainly good quality/value choices but it’s unlikely that you would find an “equivalent” mattress somewhere else outside of other mattresses that are in the same general innerspring/latex category. There is more about trying to “match” one mattress to another one in post #9 here but in most cases even seemingly minor changes between the designs of two mattresses can make a surprising difference in terms of how it feels.
There are other innerspring/latex hybrids in the Los Angeles list and some may be in lower budget ranges (you would need to spend some time on their websites or on the phone to find out what each of them have on their floor) but each of them would be different from each other so you would need to do some testing to make sure that any of them are just as good a “match” for you in terms of PPP because the suitability of a mattress is the most important part of the value of a mattress purchase (see post #13 here).
Phoenix