Southern AG brand has a concentrate. Much cheaper. just need a spray bottle.
i picked mine up at home depot.
seriously, don't buy the diluted shit in a spray bottle. just put a few mL of concentrate into 16oz and you get at least 5-10 of those diluted bottles for the same price.
Most likely it is their, it is a common pesticide. Should try using the sites "lowes homedepot exct" search function and use "pyrethrin" as the key word.
or even in google itself, "pyrethrin big box store"