Mr.MIlind before starting breeding you should have proper knowledge about canine infections like parvo,distemper,corona,etc.. i am not saying to google these words, ask doctors meet them personally & you should know the difference between puppy mills and quality breeding.
After that go for the breed which suits your nature.
and bout investment you should start with the top quality available
like if you go for a Pug or a rottweiler, buy a puppy from top breeder available.
and remember top quality means high price ! start with one pup only !
Check KCI magazine for Top Breeders and Dogs.
Dog Behaviour Specialist