— Every day, about 45 million spam text messages are sent to North American cellphones. If you don’t have a text message plan, you’ll pay around 20 cents for each one you receive. The real cost comes if you respond to those messages. At least 70 percent of all cellphone text spam is designed to defraud you in some way.   Spam in text messages may try to guide you to shady websites that will install “malware” on your phone to …