I just got Diagnosed at 38.
I'm in a psych-related field, and it took friends/ co-workers to mention it for over 5 years, along with my son being diagnosed over 2 years for me to finally go in and see someone.
I tried Ritalin LA, and it made me anxious and irritable.
I'm now on Wellbutrin, and not quite doing the job, but in MUCH better mood

.
I'm not sure about having any battery of tests, or any $1000. I went to a psychiatrist that specializes, (VERY well respected in our community) and he diagnosed me in 2 hours, prescription and all. My insurance covered visit.
The appearance of laziness is a VERY common thing with this.
Also: I don't hear it mentioned here much, but I would have to recommend "Answers to Distraction". I was written by 2 shrinks, one of which has ADHD, who are famous for writing "Driven to Distraction", a very well known ADHD book.
The difference is that "Answers" is in a FAQ or Q&A form. VERY easy for us to read, and deliberately so.
Please look into this. It's worth finding out, no matter what the problem is.