Edgar Cervantes / Android AuthorityTL;DR AT&T has announced a Build-A-Plan option. This is a customizable carrier plan starting at $15 per month for unlimited talk/text and 1GB of mobile data. You can also pay extra to add more mobile and hotspot data for your next billing cycle. Finding the right cellular plan can be a tough challenge, but what if you could simply create your own plan? Well, AT&T has just announced Build-A-Plan, which it claims is a “fully customizable” wireless plan.AT&T Build-A-Plan has a base price of $15 per month and comes with unlimited talk, unlimited texting, and 1GB…