we also sell a $40 (i think) and $90 dollar foot bed. the $40 foot bed is not customizable at all, the $90 one is somewhat customizable, but not fully.
anything is better then the stock foot bed. the stock foot bed is literally shit, take it out and bend it, it does nothing. putting in a foot bed will correct your pronation (everyone has it basically, like 10% of people supernate), which means when you step, your arch collapses and your foot spreads out. so your toes actually move forward, and the sides of your feet spread out too. so when you put footbeds in, your toes will actually be farther back (thats why i am buying a boot where my toes do touch the front without a footbed), and your foot will be narrower (well as wide as it normally is when your not putting pressure on it) which will help you fit into a smaller last.
its worth getting something... its does wonders for you foot and boot.