that's a great link that was provided.
minimum foster care rates are set by the state but they can vary county to county in california, and they can vary, depending on individual child needs/difficulties, from child to child.
generaly speaking that rate is supposed to cover all the basic needs of the child-food, housing, clothing, school supplies...but one thing you need to keep in mind with f/c is that even though it's paid out monthly-its computed on a daily rate, so if a kid is placed into your home on the 10th of a given month you will only receive a prorated amount for the days in that month the child was placed in your home. it's important to know this because kids can come into your home with only the clothes on their backs-so you have to either have a supply of clothing/toiletries on hand or go out and buy some. items you may find that cost you more than your entire first month's rate (which like the link sez-can take an initial 30-45 days to receive). likewise, if a child is placed in your home, you go to that expense, and then the placement is changed-you will only receive the rate for the days the child was there (so if it's 2 weeks-figure 14 days prorated monthly rate).
idealy the rates are supposed to cover your expenses-in reality it can be an additional expense to have a foster child. if covering your expenses is a concern-i'de say look to your existing expenses for your own kids and figure out what of those items you'de want to/need to provide a fc child-esp. if you are looking at what i'de call 'entertainment' and 'extras' (extracurriculars, doing family activities that cost per person, eating out...) then you could be looking at spending considerably more than fc provides (fc rates are intended to provide for "the minimum adequate standard of care").
another great resource of information is foster parent support groups-do a google search for sacramento county or check in the sacramento bee for a local group. these folks know the in's and out's of the local system-and can warn you of any pitfalls. some groups (like one that used to exist in contra costa) are highly organized such that members have 'sharing closets' set up-if you get a 10 year old whose size 12 you call your fc parent friend who keeps a supply of appropriate sized clothes/age appropriate toys on hand for you to borrow, if an fc friend gets a 10 month old they call you to borrow those 10 mo. clothes and baby supplies you've agreed to keep on hand and lend out (this is exactly why some fc parents are rigid in the ages of kids they will take-so they can maintin supply closets and not have repeated expenses). the groups can also tell you the good/bad about the differences in placements-emergency placements, initial placements, long-term-and the time committment for all of an average fc kid's needs.
time committment can be a big issue-some counties are realy great on providing dss staff to taxi the fc kids to all their appointments (counseling, visitations, court hearings, assessments...)-others put this on the fc parents (and it's not schedualed around your convenience).
get as much information and education as you can-some people love it, some people find it not at all what they anticipated and it becomes a very negative experience for them and their families.