Virgin Mobile has some plans at 300 minutes but at 35 a month is over double what you have now.
The ANTENNA discussion has been done before. It's still about location and your proximity to a tower.
Not prepaid, I'd prefer Verizon to be honest, but the lowest they have is 450. Sprint no longer provides a 250 minute option for "Everything Data" and their "basic" plan does not allow for smartphones. Plus, it's cheaper to go with tracphone (even over straight talk) than to pay up 29.99 a month, as I pay 20 USD every other month on my tracphone. But my tracphone's antenna is horrible.
Maybe instead, I should ask, what tracphone has the best antenna, which I can buy in-store like Walgreens, etc.