Yea that price is right, I have done it my self also, it just a huge mess, just trying to recover the used product, and strain all the crap out of , it and the thing still clogs, and they clog all the time, a real PIA,
the place I used had a product called star brite, and they claim it is a by product of aluminum mining ,and it perfectly round and wont damage the sheet metal, and they charged me $800.00,and the did it on the rotisserie,
I used play sand on some of the heavier stuff, and it could potentially do alot of damage to thin sheet metal,so yes most here agree have some one do it, it is much easier, and when you drop it off look at the place they are doing it , and you will see why it is better to have them do it.
good luck, have fun