I'm looking at a Tourmaster Nylon Cruiser III Slant Saddlebag - X-Large. It does not mention if it requires any support brackets. This support bracket is key. It would lower the overall cost of the baggage.
It has been my experience with soft saddlebags that they last a lot longer and cause less damage to the bike if saddlebag support rails are installed with them. The bags you're looking at can be mounted without them; you just remove the seat, flop the bags over the fender, replace the seat and then secure the strap at the rear of the left bag by passing it around the fender (usually under the tail light) and buckling it to the other one.
If these universal style bags fit your bike without things like the shock absorbers and signal lights intruding, they will usually last for at least a year before they start to collapse. And they will eventually collapse. By installing support rails you will increase the lifespan of the bags as well as anchor them more securely to the bike. A favourite trick of mine was to secure the bag to the support rail by using rubber encased steel cable clamps.