This number texts me on all my Craigslist ads and I know it's a scam

Agree with Bill above, scam reply to Craigslist ads!  Did same to me!

This # has tried to scam me twice on Craigslist

This is a craigslist scammer looking to send a cashier's/certified check for a purchase.  They might add money to the check and say "reimburse me" for the extra to get that amount of money from you or they might just take your delivered item.  The check will bounce after a couple weeks and your bank will hold you responsible for this amount.  Avoid this person at all costs.