The fostering fee is regarded as income and the child will be granted allowances in the same way as other children of the household. I believe some IP's offset more for the care of the child, but this would be a matter between you and your IP to discuss.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014 http://foggy.blogs.iva.co.uk