understated self employment income Will I have to pay more for Turbotax to amend?

I jumped the gun on filing my taxes and understated my self employment income by $270. I received the 1099-misc a week later showing the higher figure. I had forgotten that I had received the first two payments for my self-employment to a different bank account before I switched to the permanent one. I have such a low income that it should not make much of a difference to my total taxes, only the percent of $270 that pays for social security tax and Medicare. I have two questions: Can I skip amending the filing, and will I have to pay for a Turbotax upgrade to amend?