OT: router?

[azeem ahmad]

hi list
i got 6 different networks that are on ranges
192.168.0.0/24
192.168.1.0/24
192.168.2.0/24
192.168.3.0/24
192.168.4.0/24
192.168.5.0/24
192.168.6.0/24
i want them to communicate each other selectively, mean i want that 
192.168.0.0/24 network communicate with all other networks and other 
networks can communicate with it, but all others networks must not be able 
to communicate with each other. i think the ultimate solution is using a 
router.
m i right?
and an other thing i want a cheaper solution, can u people tell me about any 
cheaper and good router
Regards
Azeem