one year ghana visa

Whatever length of visa you have, without a resident's permit you will only get up to 90 days from the date of entry into the country.

When I first came here I had a multi entry 1 year visa, which got stamped as I arrived at the airport for 90 days. I then had to either leave and re enter the country, or get a permit extension. The extension is normally no problem (not sure how much it costs) but I suspect it might become a problem if you plan on staying a full year without leaving the country.

In terms of which visa you need, ask the NGO your working for - I would have thought they'd be sorting all of this out for you?

And I'm so sorry to be the bearer of bad news, but I should have added not sure what type of weekend job your looking for but I think you will struggle to get anything.

If you are planning on getting a job you'll have to have a work permit and these can only obtained by companies with a quota allowance - meaning you will need to have some kind of specialist skill that nationals don't have. So, no waiting, bar work, shop work etc... which would be the normal weekend jobs I'd think of (you'd be very unlikely to get something like this ahead of a national anyway).

My advice would be to forget the weekend work, come with enough money to support yourself for the full time your here and enjoy your weekends.

Unlikely you would find a job at all. In Ghana, as in all developing countries, there aren't enough jobs for its own citizens. Businesses will hire a local before they hire you for any job like bartender, wait staff, etc. People sometimes work for nothing (i.e., the guides at Elmina Castle) in the hope that they might get tips because there simply aren't any jobs. Labor in developing countries can be had for extremely low wages. Doubtful you'd want to work for next to nothing.