You'll need a 4x4 for the base, some scraps for the pad block and legs, a piece of all thread (I recommend 1/2"), two nuts and a washer and four wood screws. I also recommend that you use wood that's as dry as possible or cedar for the base, as wet wood can split when drying. I had used pressure treated wood for a couple but have replaced them due to concern for chemicals used as preservatives. If you wanted to use pressure treated wood for a garage setup, that may be okay, just be careful to clean up the sawdust and wear a mask when doing the work. The schematic shows the general principle of how to put together the business end, the "pressing mechanism".
By force fit, drill a hole that is slightly smaller than the diameter of the all-thread. Then just pound it in to the support 4x4. When you tighten it, the axial compression will hold it in but if you drill a hole too large, you may end up with some play in it.
So, after searching instructables.com for a good storage/work stand for my bicycles, I decided to make a hybrid of this one and two others (see links). I even added some extras to it to make it super useful (like some old carpet wrapped around the bottom as a scratch post for our cat and some better lighting to help in toeing-in brake pads). You'll notice in the photos that I added a coupler (I think that's what it's called) to the clamping mechanism. This coupler allows me to spin the clamp and angle the bike at any direction I need while working on it. The extra prong-thing on the clamp adds the extra strength I lose I by using a PVC clamp. All in all, the materials were super cheap, maybe $35 total, I don't remember. Even the vertical bike hook was only like $7 at Lowe's. It works great for storage and maintenance.