You know the annoyance of grabbing your smartphone when it's ringing or vibrating, only to find it's one of those annoying robocalls. The Federal Trade Commission received about 375,000 complaints a month last year. How do you curb this annoyance? There are several options. You can go into your phone settings and block the individual numbers after receiving spam calls. This is pretty fruitless, given the robocallers keep changing numbers. The Verge reports, mobile carriers offer services to help. The generally cost about $3.00 a month. AT&T offers Call Protect. If you're a sprint customer, you can get Premium Caller ID for $2.99 a month. T-Mobile offers Scam ID & Scam Block for free. Verizon customers can get Caller Name ID for $2.99 per month. I recently looked at the blocked numbers in my iphone. $3.00 a month is starting to sound pretty good.