$100.00 That's crazy money for something that cost about $20.00 and an hour with a drill and soldering iron to do yourself.
People always charge crazy money for mods. Just like the T-bird mod, a $6.00 diecast car with two leds and a resistor in it, pinballdeclas wants $136.00 for that, the real parts cost is maximum $12.00 and 10 minutes of work. Same goes for the lampost mod.
Try to do it yourself instead, you might screw up the first couple of times but you will gain experience and you really need to screw up many, many times before you get over the $100.00 mark.