Breeding dottybacks isn't that hard. They can change sex, so you would be best to buy two small juvi's like liveaquaria is saying their fish are, or buy a large one and a small one.
It is best to give the smaller fish a hiding place in the top of the tank. PVC pipe with a cap on both sides with a smaller hole drilled on one side are the best for breeding. Make sure there are more hiding spots than fish.
BTW, fridmani aren't that aggressive as far as dottybacks actually one of the most peaceful species.
And I think liveaquaria, does a good job at offering pairs. They always have clown pairs on Diver's Den, and have had some psuedo pairs of species that are more aggressive and harder to pair.
A lot of fish are easy to pair, everyone thinks of clowns though and those can take years after establishing a pair to spawn, that's why its better to buy pairs of those, but other fish are pretty easy to pair up, despite everyone belief that saltwater fish can only be kept singly.