Depending on the amount of room you have in your store, the actual size of the point of purchase displays is going to vary. Obviously you'd like to fit in as much material at the end of the store as possible, but that might actually prove more counterproductive than anything else. This is because, when there are more than just a few items, the individual's eyes are not going to land on anything specific, which makes it easier for them to simply walk past the display. You don't want them to walk past the display as it is better for you to have only a few items that actually catch their attention. This is possible by only placing a few items in the point of purchase displays. With only one or two items on display, anyone walking to check out is going to see it.
The area of the point of purchase displays is also very important as well. These point of purchase displays must be easy to see. If not, nobody is going to take any notice of them. Chances are, you have gone to a store where the point of purchase displays is located under the checkout register. With everything out of sight, out of mind, unless you act waiting in an extended line and your sight is shifting, chances are you didn't see anything on the display at all. This is why you want something at eye level. Eye level is going to force someone to see the item, even if they were trying to avoid it. The prime visual location is essential in making the final sales. In a traditional grocery store, the most valuable items are placed at eye level, so it is easy to see. You need to do the same with the final point of sale displays.
People are going to need different items at different times of the year. During the summer time, someone is probably not going to need cold and flu medicine. Likewise, in the summer months, they probably are not going to need suntan lotion. This is why you need to utilize seasonal displays in your store. Make sure to place high profile items that someone is going to need right there. This way, a person is more likely to make the purchase. They might not have a cold during the winter yet, but they might decide to purchase the medicine, just in case. Having it right there ensures they pick it up, even if they didn't walk down the specific isle.
Don't put anything on the final display that is going to cost an excessive amount. Instead, focus on items that are only a few dollars. This way, the customer won't mind spending the few extra dollars. Chapstick for the winter months is a good idea, as are simple allergy items for the spring time of year.