Received as a text, it is spam.  You can report this to your carrier.  Forward the spam to your carrier by sending it 7726 (spells spam).  They will file the complaint and if enough complaints are lodges they will shut the number down and file criminal charges.

received text message from 347-556-8520  around 1820hrs EDST stating my "entry last month had won"
and to go to bestbuy.com.gpgc.biz/ and enter Winning Code "6655" to claim my "FREE $1,000 Bestbuy Giftcard"

Received text:

Your entry last month has WON! Go to www.bestbuy.com.gpgc.biz and enter your Winning Code: "6655" to claim your FREE $1000 BestBuy GiftCard!