In my opinion the most realistic color contacts are Acuvue color contacts followed by FreshLook color contacts. With Acuvue color contacts you can wow people without having them say to themsleves "yeah but those are fake eye color contacts".
Now to get Acuvue color contacts or really any of the most realistic color contacts you will want to go to AC Lens or 1 800 contacts to get them. Both will give you discounts for buying online and for buying in bulk. You can get a variety of the most realistic color contacts in the most realistic colors.