Straight Talk is a joint venture prepaid cell phone between America Movil (Tracfone, Net10) and Wal-Mart. Straight Talk offers a range of phones from your basic flip phone to full featured smart phones all for either $30/mo (limited) or $45/mo unlimited.
Straight Talk uses Verizon, AT&T, and Sprint towers depending on the model phone you chose. Make sure you ask people around town what phone carrier they use and buy your phone accordingly. See what models use which carrier here.