POTOMAC FALLS, Virginia (CNN) -- Parents of children with autism often say it's like being on a roller coaster 24 hours a day. And the ticket for the ride is jaw-droppingly expensive.

A family's lifetime costs for caring for a child with autism can reach as high as $5 million, according to the Autism Society of America. Each month, parents report they pay thousands of dollars for treatment and therapy. And in most cases, insurance, even good insurance, won't cover all of the fees.

Some parents are making big financial sacrifices just so they can provide the care their children so desperately need. Many families faced with autism are so financially strapped they second mortgage their homes, live with other family members, even file bankruptcy, according to Autism Speaks, a national advocacy group.

For Carol and Rick Nunez of Potomac Falls, Virginia, the stack of bills piled up on the dining room table is a brutal reminder of their reality. The Nunezes, parents of two boys, were introduced to autism when their younger son, Ethan, was found to have the condition two years ago.