The most important aspect of all these gifts is that they're branded with the 888 logo, and they match the casinos color scheme, to make it more recognizable.
The free gifts add a huge incentive to consumers to deposit their money into the casino, where the casino is more than likely going to win. So despite the fact 888 may lose a small amount of money on the promotional gifts, they will earn it back from those who deposit into the casino eventually.
The products they've used for this campaign are all relatively generic, which means this type of campaign can easily be run on a tight budget.
As you can see from the image, they have also linked it to another casino website, CasinosOnline, who they are likely in partnership with. So not only does this campaign add brand awareness, it also helps to drive website traffic, as this campaign was run online.