YMMV, ComEd customers only.
Just got an email from ComEd about flash sale for Nest 3rd Gen thermostat. On sale for $199 with $100 instant rebate = $99.
"$100 INSTANT REBATE
ComEd customers with central A/C receive an instant $100 off rebate on a qualified smart thermostat. Limit two (2) rebates per account."