I made mine, got me a small piece of sheet metal, some gasket, and drilled the holes to fit, also trimmed the piece of metal to fit on the EGR tube. took maybe an hour to do.
cut the gasket to the size of the metal and add some gasket sealant and wha la.
EGR block-off plate.
cost
sheet metal from lowes----20.00 est
gasket meterial----- 10.00 est
gasket sealant-----4.00 est
total-----34.00

would be a lot cheaper if you can just find a small piece of sheet metal, about an 1/8th inch thick.
that price was when i went to look at getting a piece, but i wound up getting it from work. All i really had to buy was the gasket meterial.
so in essance it cost me 4.00