there are tons of nepalese owning gas stations in texas.Well one of my friend owns one in dallas texas.According to him  buying a gas station costs from $40,000- $2 million. It depends from inside sale and if ur buying the property or on a lease basis.Average profit margin is 30-40%.It all depends on competition and products like water,sodas, gums, candy say 50%-150%.Beer 15%- 30%. Tobacco 10%- 20%. Lottery 5%.Gas negligible.Check cashing 1%. Well some stores got a fast food inside like selling tacos burgers. And not to forget Cherry Machines.U can make game changing $$ if u know how to do it.but unfortunately my friend's store does not have slot machine coz the city where his store is does not permit cherry machines.