Primers are key for a long lasting makeup.They help to conceal imperfections and allow the foundation to last much longer. My ultimate favorite and the one I always keep in my makeup box is SmashBox Photo Finish Foundation Primer, is oil free, it lasts forever it also works for almost every skin type.
It leaves a silky finish and is odor free. Although it is a little more pricey than other primers, if you are looking for something that is proven to work this is the one I would recommend. Definitely a must have for me.