I bought some Goji berries last year. However, not knowing what effect I could expect, and not experiencing anything that could be construed as beneficial, I failed to make judgement. That, combined with the fact they taste like burnt rubber and cat p1ss, prompted me to call it a day.
The one thing I would recommend is fresh orange juice. I've drunk about a litre a day for the past 8 years. Prior to that I used to get two or three colds a year. In the 8 years since I've only had one, and that was when I went away for a few days and couldn't get hold of fresh juice.