Simple Products

Hi! I sell cellphone cases and I was on a dilemma whether I should categorize them as “simple product” or “variable product” You can view few of my products here: http://www.wordpress.casemestore.com/shop

They are unique products so I initially thought they’re just simple products. I want to have a “other colors available” feature such as this one

Can you recommend any plug in like this? Since they’re only related products, is it still necessary to categorize them as variable products?

Please advise, thank you 🙂