I can only comment from a UK POV but since I have been through the state care system, 15 years in state homes, and now work in an environment that is all too often the end result of that system (I work in a prison) I reckon I have one or two insights.
Firstly, state care is a complete disaster area, around 66% of all those who wind up in long-term state care end up in prison where they make up around 33% of the population, what’s more these are the ones who just keep on coming back for more.They become so institutionalised that jail is the only way they can get some semblance of order into their lives.
The causes are not hard to discover, to the care workers you are merely a job (from which they are entitled to take holidays - think about that for a moment), they may start off idealistic but when they find that their views are over ruled by social workers who often never even see their subjects, along with the fact that looking after your own children is hard enough, never mind possibly disfunctional others it does not take long to grind them down.
The environment is far more petty and competitive than in most family situations and because there are usually far more children to look after per adult it is unlikely that the carers can attend school PA evenings or the small things that parents usually do.
There is rarely the continuity that a child needs, I personally went through 5 sets of guardians by the time of 5 years age, some have it far worse with custody disputes between relatives such as Aunts and Uncles, social services, and the natural parents.
Add into that that often the children have been placed in care due to years of violent abuse or neglect and the almost complete lack of counselling support, along with growing up with other children who may well have serious personality problems and mental illness and you can see why foster homes are without doubt the best option.
There are two types of foster home, long and short term, the short termers are usually respite care for parents who are temporarily disabled, like car accidents or maybe in jail.Those are the ones who are most likely to get moved around.
Short term carers never know what they will get until a child walks through the door but it is an absolutely vital role, sometimes it is not possible for the child to return and they may volunteer to be a long term carer.
In long term care the child is usually already a resident in state care in a group home, they will be introduced over a period of time with afternoon visits which will then go on to weekends and school holidays and then on to more permanent arrangements.
Foster care is not adoption and so the rules on same race parents and others are not as strictly enforced, but foster parents are vetted.
It is a very good idea to be a parent yourself, its virtually essential, ideally your own children will be more mature than their years, it is a massive stigma for a child to be placed in a foster home they will find it extremely difficult to understand that a parent can be as even handed with foster children as with their own. You will always get this thrown in your face when the foster child is emotional, unfortunately children from state care are not always very empathic, grateful, and quite often are immature.
From the foster childs POV why should they trust anything and anybody, no-one can be relied upon and you have to get what you can for yourself.Yes they are selfish.
It will help you a good deal if you have an extended family, the experience of grandparents is a godsend for example, but having plenty of nephews and neices gives the foster child a sense of order and place as well as role models.
Unless things have changed dramatically I would not hope for too much practical support from social services, in fact in one case I know of the Social Services did not pass vital information on the the foster parent saying that it was confidential and this led directly to the failure of that placement.
Social Services staff seem to think that because they have done one or two college courses that they know more about children than real parents, not many of these staff have children themselves I notice.
The reward is watching and seeing a child grow from an odds against case to a responsible mature adult, you would know that you have made a positive contribution to society but also and far more important you will enrich yours and the childs life beyond measure.The child usually does fit in and eventually becomes the same as other kids fortunately children can be very resilient to the worst that life hurls at them as long as someone cares enough about them.
IMHO fostering or adoption are possibly the greatest contributions that a parent can make in life in almost every way.
You asked about the money side of thing almost in an embarassed sort of way but money, or lack of it, has been the root cause of many a matrimonial breakdown and the arrival of children often stretches family finances to breaking point.
You need financial support, it is in the interests of all concerned, including the public, that you are supported generously, too often people look on accepting money for a carers role as being mercenary but you must look on it as a tool to enable and empower you.
I have heard of cases where the income from the state to foster parents is treated by the carer as a business, all I can say is that good professional parenting is worth every penny, I have not come across places where you can take a diploma in being a good parent, experience is a hard won and valuable asset.