Can you help me with a source for demographic information?

The census publishes for free the demographic information they collect in area blocks. There are some services that allow you to specify a specific location and then gives you the demographics in distance rings you specify, like 1 mile, 5 mile and 10 mile. Most of the services that provide this are annual subscriptions for a high price tag. Can anyone suggest an online service or method for getting this information one property/report at a time?