As the title says...
1. Register for Amex promo of $20 off bestbuy $199 purchase (valid thru 12/31) if you havent already done so.
2. Go to BB, get the Nest thermostat, price match to micorcenter $199.99+tax in 1 transaction on your amex card and receive the $50 BB gift card for buying nest thermostat. This will trigger $20 amex offer
3. Then get the nest cam price match to microcenter $149.99+tax and apply $50 gift card in another transaction for a total of $100 + tax. This transaction can be on a different card

Final total ($300+tax-$20 amex promo) = $280+tax
receipt enclosed as proof

Microcenter price links
http://www.microcenter.com/product/452914/Learning_Thermostat
http://www.microcenter.com/product/452790/Nest_Cam_security_came...