If you have access to a lot of free apples, you can easily make cider from them. Any apples will do, but they should be as ripe as possible. This instructable shows you a simple method that does not require any special equipment.
Update Oct 2014 - In response to popular demand, I have just published an extra Instructable about how to make the press in step 4. Just wood, a few plastic containers and a car jack - cheap but very effective :)
Step 1: Collecting your apples
The first thing is to get some apples. You will need quite a lot of large containers, because you need to collect about 4 to 5 times the volume of apples compared to the volume of juice you want to make into cider. The container shown here is a 5 gallon (22 litre) fermentation bin.
A sheet or blanket is also handy. Put your sheet under the tree, climb up the tree and shake it. Lots fall off. The advantage of this method is that generally the ripest apples tend to fall off, and seriously under-ripe apples stay on. When you put them into the bucket, pick the apples up by hand, so you don't get all the twigs, leaves, earwigs etc.