Mulling converting my carport to a garage

I'm just in the beginning stages, so I haven't called in for any estimates.

1. Is it generally worth it return-on-investment-wise when you sell a house?
2. Any idea how much it might cost?

Additional info, if needed: I currently have an attached 2-car carport. 2 sides are walled/finished. The 3rd side is a brick wall halfway up then 2 wooden columns for the other half. I would close in the open half of that wall with bricks. The open side is 19-20 ft. A standard double garage door is 16 feet, I believe, so I'd have to brick a few feet on that side too.

I'm not putting windows in, on the garage door or the currently half-open wall. I'm also not putting in doors, as I already have 1. It does not need to be insulated, have water run, or have electricity run (there's already electricity run to where the garage door opener would be).

I'm thinking all I'd need to pay for is bricks/mortar, garage door/opener, labor (if I pay someone to do it) Anyone have any experience with this and can give some feedback?

I'll hang up and listen.