Sadly this isn't bull. Most newer keys have a passive anti theft system (PATS) where there is a chip inside the key body that allows your car to crank when the key is turned. There is a procedure to program spare keys yourself for only the cost of the key blank and cut, but you HAVE to have 2 keys already programmed to the car to do it. If you only have 1 key left, you can't program it yourself and have to go to ford to get it done for you. $110 is unfortunately what they charge. Maybe there is a DIY workaround, but I haven't heard of one.
If you get your key replaced, look up the PATS programming procedure and make yourself some extras. The blanks are pretty cheap on ebay.
2006 Black Mustang GT Coupe
Flows, C&L CAI, SCT tuner from Doug, PI 3000 stall lockup converter, Pypes O/R H-Pipe, Spydershaft, Automber Cobalt Trans
temp and oil pressure gauges, Innovate Wideband, SOS A-Pillar replacement, Meziere eH2O pump, FRPP 3.73s, J&M 3 Link, Pioneer Avic-D3, Grillcraft replacement grilles