You need to sand off the shine before you put anything on it, otherwise paint will peel and stain won't get in. If you want it to look wood-ish, use stain. The easiest/cheapest way would be paint. Sand it JUST enough to get the shine off, use fine grade, so you don't have noticable lines. Paint does best with a few light coats that dry in between... 1st coat will not really cover much. It's ok. Let it dry, do it again. If you mess up, sand that spot a little, and do it again. It's up to you, if you have the area to do spray paint, cover the chair with a trash bag and go outside .. not next to cars or anything, and not if it's at all windy, cz dirt will get in paint.