After you defeat Flannery and exit the gym, your rival will appear and give you the Go Goggles. As long as you have these in your bag you can walk through the sandstorm without any trouble.
Like ruby and sapphire, it is north of slateport city, south of mauville city. Easier to reach from slateport city.
Slateport city.
slateport city Pokemon mart
the third badge in sapphire is at mauville city(north of slateport city)
The Name Rater is in Slateport City, in the building to the left of the Pokemon Center.
You get it from the little girl in slateport city
There isn't one.
In Slateport City, to the left of the Pokemon center.
In Slateport City, the contest hall is close to the northern exit, just to the left of it.
You have to evolve a gulpin, which are common in the area above Slateport City
Oceanic Museum in Slateport City
North of Slateport city on route 110.