If you're thinking of starting a SW system on a tight budget, you may as well stick with FW. The number one cause of failure for people starting out a SW system is going cheap or lowest rate on the equipment. Do the research on the best equipment for the set up you want and save for it. Or buy the equipment piece by piece until you have everything needed to set the system up. Mostly, resist the temptation to start buying any fish that catches your interest and stick to the species that fit your plan. It'll save you alot of headaches later.