Because of the low amount of dollars used, it is easier to use cents. 500 cents will buy you 250 text messages. You now need to find how much it cost to do one text message. Divide the price for 250 by the amount, and you will find that each text cost 2 cents. Now multiply by the 300 texts to find the total amount. 2 cents times 300 messages is 600 cents, or $6.
$6