My son is a college student, & dependent. He earned about $7700 in 2016, and should get a refund. Do I have to pay another $49 for doing his return in Turbo Tax?

Yes, The Online version is only good for 1 return. But you can use the same email address for 5 accounts.  To do another return you have to set up a new account and new user name and pay any fees again.  He can probably use the Free Edition.

How to start another return in the Online version
https://ttlc.intuit.com/replies/3288574

OR There is also The Turbo Tax Freedom website which is free for federal and state.  And has more forms than the Federal Free Edition, like the full 1040 return and Schedules A, B, C , D, E, F, EIC, H, K-1, SE,  etc.

To qualify for the Tax Freedom website  you just need to meet one of these 3 things
AGI $33,000 or less
Active duty military with AGI of $64,000 or less
OR qualify for EIC (earned income credit.)

In order to use the Tax Freedom Edition, you have to start it at a special website:
http://turbotax.intuit.com/taxfreedom/

When you get to Tax Freedom use the link to "I Qualify, Start Now" at the bottom instead of the sign in link. And you have to create a new account, if you use the same account info it will take you back to Turbo Tax.

How to switch to the Tax Freedom edition
https://ttlc.intuit.com/replies/3491786

Don't reuse your Online account or you will lose your own tax return information.