So I want to get a heavy bag at my local Big5 sports. They have 80lb heavy bags for $64.99 and 12 or 16 oz gloves for $24.99. Also they have a Wavemaster Super X Free-Standing Heavy Bag that you apparently fill the base with water or sand for $120 (comes with gloves, jump rope, and DVD).
However as William Hung once said, "I have no professional training". In fact I have no training at all, I don't really even know how to throw a proper jab, cross, hook, or uppercut. I just want a bag to take out frustration, burn calories, and lean some basic strikes, and just have some fun.

#1 - Is this worth it at all or am I just going to get bored b/c I don't know what to do. I read of lot of the other heavy bag threads but didn't really answer my question as most people here have training in some boxing or martial art form.

#2 - So what size bag would I need? I'm obviously a total newbie at this. I'm 6'1" about 185 pounds and do lift weights and run quite a bit, so I'm in OK shape. 70, 80, 100lbs? I can get a used 70 pounder for $30 right now, would this be a waste as a first bag, should I just right to 100lb?

#3 - So I would use hand wraps, and then at that point do you use "bag gloves", do you use 12oz boxing gloves? 16oz boxing gloves? I'm really not looking to get into competition so probably whatever gives me the best workout. It just seems those bag gloves don't have much padding but 16oz boxing gloves would be bulky, no?

Sorry for the first long post, any help is appreciated