Just because something is priced lower than market doesn't make it a scam and neither does no phone # being listed.
Clearly if something is worth 10k plus and it's listed for $2k and you send money to them, that's just foolish. That being said, I've bought stuff worth $1500-2000 for $200-500 in person without flaw. Don't send money to some random stranger on craigslist, sometimes there is good deals that seem too good to be true but are legit and somebody just needs the money. But don't be an idiot and send money to someone who's selling it for their friend or who is overseas and can't meet in person. That's the oldest scam in the book.
I list 5-10 things for sale on craigslist per month. I don't put my phone number because when I do, i get spam phone calls for weeks. If someone emails me and seems legit I'll give them my number. I have never had a problem on craigslist with this method even contacting someone else through email. If the ad isn't in the same format as other craigslist ads (such as bolded text, bigger words etc) chances are it is a scam.

Phone number anyone can buy a magickJak for like $40 and pick any area code and appear to have a local number.

Go to any internet caf� and post an add using the MagicJak number and have the money sent via Western Union or other money transfer system and not a darn thing the US authorities can do to touch the scammer.

Damn nigerians!

No phone number to reply to do not waste your time.