Here in South America, I have over 30 Aloe Vera plants in my yard. It matures to a size ready to be used here in about a year and a half and produces baby plants, so my family has an overabundant supply (in the US it may take three to five years to mature to the same size). We have taken some to the local market and sold it, but mostly grow it for home use. To make your own gel at home, learn how to fillet the leaf, remove the aloin, blend and then store properly in the refrigerator. Then you can make products with it like my favorite, shampoo!!
Filleting the Aloe Vera
A leaf of Aloe Vera will produce over a cup of gel for my family and I. I cut it as close to the stem as I can in order to get as much gel out of the leaf as possible. I watched a video on YouTube to learn how to cut the skin off and fillet the leaf.
Remove the Aloin
After I have filleted the Aloe Vera, I try to remove all of the aloin from it, which is a yellow liquid contained in the skin of the plant which acts as a laxative if consumed. My Ecuadorian friends taught me their method for this. I put the fillets to soak in purified water for about 5 minutes. Then I cut off any yellow or green bits of skin still on the translucent fillet. Aloin is very bitter and the FDA in the US has rated it as a possible carcinogenic or cancer producing substance. My friends here in Ecuador were taught by their mothers and grandmothers to remove it because it was said to be irritating to the skin as well as because of the bitter taste that it has. 
Blend Into Gel
I take the Aloe Vera out of the purified water and cut it into sections before I put it in the blender. I add Vitamin C to help it last longer and a few drops of essential oil. I use the Vitamin C tablets that my children take as vitamins. I enjoy adding mint essential oil because it gives the gel a soothing smell. I blend it with my smoothie button, which gives it a foamy consistency. I have also heard that adding Vitamin E to the gel works as a preservative.
Store in the Refrigerator
The gel lasts longer when stored in the refrigerator. You will know if it is going bad by the acidic smell it starts to take on. I have been told it will last 4 months in the refrigerator, but we use it up more quickly, so I am not sure.
We use the Aloe Vera gel for all sorts of household uses including spreading on sunburns and scraped knees, as lip balm, skin moisturizer and in shampoos and detanglers. My favorite is shampoo. After the gel is made I add one part vinager and one part honey to two parts aloe vera and a little bit of comercial shampoo to make it suds. I shake it up in a shampoo bottle before I use it and each time that I use it. It makes my hair clean and shiny without irritating my skin like some comercial shampoos do. Aloe Vera has so many benefits!!