Looking into adoption...

We have been talking for a long time about adopting another little one to join our family and have recently felt the urge to get it going.  We filled out an application for LDS Family Services.  It's a 6-month to 2-year average wait to adopt.  I have a friend who is starting to do foster care for infants only.  She said it's a lot less expensive to go that route.  My concerns about doing foster care are: that my kids will get too attached to a baby and then have that baby leave us, and that change is such a HUGE thing for Sam that if there's too many babies coming and going then he'll get discouraged (as will the girls) and want to give up.  I really hope the waiting won't take long.