First off, I would like to apologize in advance if my English is not good enough since I am not a native speaker. Please excuse me.
Now, regarding your question,
Now, I believed Hume's definition for being free, to be that if you are doing what you want to do, you are free. However, I am doubting whether it's not that being free means that you are able to do or not do something, depending on what you want. So, which definition is it? Or are they both wrong? And does being free imply that you are acting out of free will?
Now, here personally to me I think you might have misread his theory or just his work was too ambiguous for you to understand "precisely".
Simply, Devid Hume was deterministic, more simply saying he said "there is no free will".
His study into the inductive reasoning, later led to the materialism.
The inductive reasoning, needs the strong evidences to support the conclusion.
If you swap the above "conclusion" with "free will", then I think you might be able to
understand his way of thinking. He virtually denied the "free will" in terms of its "literal" ( here free ) definition.
But please do not misunderstand, I would like to apologize if it sounds to you perplexing, but he did not deny the free will.
He meant, by free, that the free-dom can NOT stand itself alone, but although it is called free, the free-dom requires some empirical support. For example, you chose to go shopping to buy food. Your choice itself in that instant only is certainly free, but what Hume said was that there was a cause ( or the reasons in the past ) that had triggered you to choose to act so.
I hope I could have helped you to any extent.