Someone answered my question within a comment how can I give them credit?
I went ahead and posted his answer, gave him credit it in the answer and selected it an the asnwer. is this considered sloppy?
I normally comment on the comment (which you can do on your own questions before you get the site-wide comment privilege) stating that this has solved my problem and prompting the user to post it as an answer.
After a period of time, if they haven't added an answer, and no-one else has provided a more detailed answer, I would post it as the answer, calling out the comment and accepting it (when able - you have to wait before you can accept your own answers).
We could almost do with a "Make this comment an answer" type mod tool as well as the "Make this answer a comment".