Yes, it is cheaper to stack a switch on the top of a four port router, but I think you are right that an 8 port router is better all in all. Here is why, first the cost isn't that different if you have to buy two devices. Second, the 8 port router will likely have more features as it will be more geared to business use. Third, the port probably will have more address space to remember addresses. Look at Linksys or Dlink for these for home use. Stay away from no name off brand routers, they run hot and give a lot of problems.
Here in Tampa where it's usually too hot and the bugs and gators are usually too big. Tampa Computer Repair