I could write a book on this topic. Ultimately, yes, get the $600 Orthodicts. You may have Plantar Faciitis, which is a common condition and very painful. I had steroid injections in both feet several times, was on Celebrex for months, and iced them regularly to get the PF to go away. And, I got the Orthodicts and wear them dutifully.
A little history... I have always had flat feet and spent 18 years growing up figure skating, running long distance, and ballet dancing, so my feet have been beaten to a pulp (and I'm 30).
My doctor is a Sports Orthopedic Podiatrist www.posmc.com