Here is my water hole I created last Spring in sandy loam soil. I did not use a liner and went the sodium bentonite route. Downside to using sodium bentonite is eventually over a few to 5 years you may have to add some more bentonite to the water hole to seal it up again. Plus side is its relatively inexpensive and you just spread it over the water and will seal up as it falls to the bottom. Since I have added this to my property, I have had deer frequently using it along with fawns using it often. Even though I have roughly a 20 acre beaver pond, the deer would rather us this instead. It is placed close to bedding and my food plots so everything is in one general area and close to everything else the deer need. Just thought I would show you all.
Heres a good article on it and the same method of using the pail and different methods for mixing it in and spreading it out. This says 50lbs covers 100sqft but I took into consideration that the deer will sink into the soil a little too so I wanted to make sure I had a good liner of it down.
http://www.farmersassociation.com/farm-supply/miscellaneous/bentonite-clay-50lb-bag
I have sandy loam soil and have had this water hole for 2 years now. I have not had any issues so far so I am happy with it. If you can find a liner for a decent price it may be worth it but so far bentonite has been working great for me. I took a 5 gallon bucket and drilled some holes in the bottom of it that were about 3/8" in diameter. I then filled the bucket up with the soil type I was making my water hole in. leave about 6 - 8" space from the top of the bucket for pouring water. I filled the rest of the bucket up with water and watched the water slowly drain through and out the bottom of the bucket. I dumped out the wet soil and added dry soil back in. Then I weighed out 1 pound of bentonite and spread it out on top of the soil in the bucket. After that I mixed the top 1" of soil in with the bentonite and then added another pound of bentonite on top of that but didn't mix that in. Then I filled the top of the bucket with water again. I let it sit over night and the next day the water level never dropped. I ran a stick through it a few times and never saw any water level loss. I went with about 2 pounds that I mixed in and then another pound I figured as a top layer. If you do try it I would test out your soil in a bucket to give a better estimate on how much you need to get. The diameter of the 5 gallon bucket is really close to a square foot. This test tells me how many pounds of bentonite I need per square foot of soil. Also you want to use sodium bentonite (bentonite clay) and not calcium bentonite.
Nearest bentonite dealer to me is over 100 miles might be worth it though!!