What are your intensions for this mineral lick? Are you just trying to attract more deer to hunt or are you looking for a product that will provide nutrition for the herd and help with the animals overall health? There are quite a few different products on the market and they are certainly not all created equal.
For instance if you are just trying to attract deer I would suggest a product like Deer cocaine. Deer will find it and seek it out although it benefits the deer very little. On the other hand a product such as Whitetail institute 30.06 mineral is designed to fit the gaps in a deer’s diet and to be beneficial for the deer. They also make a 30.06 w/ protien to help with antler development. It ultimately depends on what you want to accomplish as to what you should buy. If you're just looking to attract deer it may even be better to make a mineral site. it is cheaper and effective for attracting animals.
***Edit***
I'm attaching a link on minerals and how they benefit deer. I hope you enjoy.
http://www.whitetailinstitute.com/in.../mar04/10.html