There are a lot of people lining up to throw stones awful quickly here.
Wouldn't you say it's perfectly reasonable that somebody heard OP has a 15 year old car and recommend that he replace the timing belt before he destroys his engine? If you don't know the ecotecs well, it's perfectly reasonable to assume that a small 4-cylinder has a timing belt. It might just be someone looking out for him. Better safe than sorry.
Or second - maybe the OP himself has already had a failure diagnosed and simply didn't realize there was a difference between the two? If he's asking for cost, he's obviously not a DIY'er and just made an innocent mistake.
2007 Solstice GXP
#3 ASP, DET and NWOR SCCA
"It's a Kappa - not a classic"