Well from what you tell me I would recommend the $30 T-Mobile plan, As for coverage, all depends if T-Mobile has coverage in your area with their 1900MHz HSPA+, check my thread: https://forums.macrumors.com/threads/1356522/
Simple Mobile $40 plan is really ****** if you are a internet user and need decent amount of data...250MB goes by really fast.
Consider Net10 AT&T SIM with 1.5GB Data if T-Mobile doesn't have enough coverage in your area, its $45/month...first month might cost you a little more but after that start getting refills from eBay...best place to get them.
Summary:
#1: T-Mobile $30 Plan
#2: Net10 $45 ($50 w/out autopay) <- Try to get refills done from eBay sellers..
I am currently on Straight Talk and get my monthly refills from eBay every month ranging from $30-$38...
Is straight talk good ? I'm in Southern California. Los Angeles. How's the data speed for you? Honestly I barely use minutes data is big thing would be nice to get 4g someday also with these cheap plans.