I recently got this email from freebitco (other may get this too) showing my total interest earned and remember i did not lock any of my bitcoins.
To see the total interest you have earned on your bitcoin balance so far, you can also go to "Earn BTC" tab on the website.
Also note that there is no such thing as lock bitcoin on freebitco at all.
You will see on that page that interest on bitcoin is automatic, "All you need to do is maintain a balance of at least 30,000 satoshi (0.0003 BTC) in your FreeBitco.in account"
By the way, if we gather fun tokens on freebitco, do we also get interest on them as well?
You get interest on your FUN tokens balance, only if you lock them.
And the longer you lock them for the higher the interest is for that duration.