There is a mandatory safety class you have to take where they walk you around the shop and make sure that you know how each major machine works and general shop safety. You also have to sign a waiver saying you are participating at your own risk. You DO NOT have to take that safety class if you are signing up for one of their classes. They will cover those basics during the class.
You can buy sandpaper, glue, and other consumables from them for a nominal price. Their hand tools are propitiatory though so you would have to buy a specific kind of orbital sandpaper, for example. You couldn't just get generic. They are reasonably priced though. There is literally a coffee can with money in it and prices written on the boxes with these consumables. If you think you might burn through enough sand paper on something, check the brand and price shop.
I agree that even at 12x12, things'll be "cozy" inside. That's OK. Keep in mind that this will be a general purpose hobby shed, not just a wood working shed. Even 12x8 would be plenty big enough for building 1 meter wingspan bungee launched RC gliders. And for the electronics projects I do, I only need enough workbench space to do some soldering with a 3rd hand (for electric guitar pedals). If I need more room than the shed offers for wood working projects, I'll just roll the table saw down a ramp and do my cutting outside in the sun.

This table top is also made from the hardest wood out of any manufacturer we reviewed: oak. In fairness, this can be both a blessing and a curse. The oak wood is extremely durable and noted for its lack of a porous nature. This means the top can withstand plenty of abuse from tool and workpieces. Moreover, you will not have to worry about liquids like lacquers and stains from being absorbed into the top. That said, the hard oak can also do a number on tool sharpness, dulling them prematurely if they are not carefully handled.
Working with wood fresh from the log, this green woodworking project is the perfect introduction to edge tools and wood grain.  In the first week you will produce a three-legged stool using buck and “whip”saws for crosscutting the log to length; wedges and froes for splitting out leg stock; drawknife and spokeshaves at a shaving horse for shaping the legs; and using travishers, rounding planes and specialized rasps for shaping the seat.
Cerritos College Woodworking, one of the finest woodworking schools in Southern California, offers classes in furniture making, cabinetmaking, CNC woodworking, and related topics.  Cerritos is the school for you, whether your goal is to acquire new knowledge, gain confidence in or improve your skills, enter the field of professional woodworking, or develop a rewarding hobby.
Making an art or a design on a wooden piece is a hectic task and requires good art skills. But there is another much easier way to carve a beautiful art on any wood surface. For this, you will need the image or graphic that you want to transfer, a piece of wood, freezer paper, etc. I, myself have made several such designs. At the source below, you can find a step by step guide for transferring a graphic image to the wood.
What I did, when I came back, was to clamp down the strip where it had torn away, and then to start routing from the other end. I still moved the router from right to left, but I did it in six-inch sections, taking light passes, and sort of whittled the strip flush. As the sections I was working were farther to the right, the strip was thinner. Eventually I came to where I was trimming the strip away entirely, at which point I took off the clamps and the remainder fell away.
The course successfully meets the needs of multiple experience levels in a safe, well equipped, spacious, congenial, and educational environment. All instruction and lab experience is under the personal direction of master woodworkers as well as one or two additional experienced woodworkers/teacher assistants who are on hand during all lab hours providing roughly a three-to-one student-to-instructor ratio. Intermediate to more advanced students should not be put off by the fact that beginners are also included in this course.  Check out some of the work done by our alumni in the Alumni Furniture Gallery to get an idea of what our students are capable of.
I live in VA and my workshop is an unheated, uninsulated garage. I work out there year round, even when temps are below freezing. I can't say it's comfortable in the winter (or when it's 100 degrees with 95% humidity) but I haven't had any major issues. I have had some big box green wood warp on me after I built a couple bookshelves and brought them into the house, but that was more a factor of the green wood than my "shop".
I am new to woodworking. I'm learning as I go along, and I'm documenting as I learn, in the hope of being helpful to other novices. On the range from slap-dash to deliberate, my method is definitely on the deliberate side. If you have enough experience to be confident in using techniques that are more time-efficient, go for it. The techniques I'm using are those I thought least likely to go wrong, not those that would produce a product in the shortest time or at the lowest cost. You'll notice that I made a number of mistakes, spent considerable time on work I later determined to be unnecessary, and in a number of cases I used different techniques at the end than I did at the beginning. These are all the result of learning. I thought it would be better to demonstrate how I made errors, and how I corrected them, than to provide a set of instructions that presented the false impression that everything went together perfectly.

I don't see anywhere you mentioned the over all length of the bench top. A piece of 1 1/2" x 25" x 8' glued edge oak at Lumber Liquidators costs $192 including tax. Two piece is almost $400! Would that be better if I use two IKEA 1 1/4" x 25" x 74" solid Beech ($99 each plus tax) on top of a layer of 3/4" Birch plywood. That would be 3 1/4" over all.
This is my first post here but been lurking for a while. I am currently working in a 10x14 shed which has sufficed nicely until my recent purchase (sunday) of a new Craftsman table saw model OR35505. This I discovered ate a lot of space but with some reorganization and some good casters, it's going to work. I did add a window AC unit and will need to figure out some heat but hoping to have built a better shop with HVAC before it's too cold.
This is technically a vanity factor, though the ability to store tools and other supplies at quick reach can be a time and energy saver. At the least, you will want a bench that comes with a shelf underneath. This will allow the storage of larger items that can otherwise be difficult to find a place for. Drawers are the other popular storage for benches and can make retrieving tools much easier – just make sure the inside of the drawer is lined with felt or the wood may prematurely dull your tools.
I agree that I might quickly outgrow a 12x8 shed. Lowes also offers a 12x10 Rancher (same style, but more room), but the 12x10 is 9 feet, 4 inches high, and my community only allows a maximum height of 9 feet. The 12x8 is exactly 9 feet high. I'm afraid of getting "out of spec" if I exceed the height limit and then getting in trouble with the Home Owner's Association. Having said that, 12x10 would be about the biggest size I could get for the available area in my back yard, so even if I hire a shed contractor to do this, the shed would have to be 12x10 or smaller.