The last time, when they gave me the run around, I had to come back several times, and it seems like they were given me the run-around. Because of my extensive tourist visas, work visa, volunteer visa, etc, I always assumed they were given me the run around because quite obviously I am willing to pay an agent.
I have had the standard vision tests, and glasses replaced a few times here. It's certainly a lot less expensive.. You can always spend more but my last pair of glasses costs about $200/USD. In the US, ten years ago, that would have started at $200 and by the time I am done paying for frames, exam, lenses, lens extras, $500.
They often send people away to get some other piece of paper, And they'll do it to the same individual many times, instead of tell them all the paperwork they need. Of course, they don't need any of that if the person pays an agent.
The extra tea money they generate goes to feed their families. I don't blame them but its a pain in the ass.
B) For price comparison, my condo does it for me for a fee of 100 baht
C) You can do it online
D) You can do it yourself, if your landlord provides you a contract, letter granting your permission to file the TM30, and signed photo of his ID/Passport.
At least that is the case in Pattaya.
EDIT: As seen in some of the other comments, doing it yourself may require photo copies of some other paperwork (chenute/deed, house book, I am not entirely sure what will be require).