It really depends on what sex your current animals are to decide what females to invest in. But I'd say Clowns, I know you said females but I would invest in a powerful male like a spotnose clown and put him to most of your females. Spotnose het females were 300 last year and 600 this year add another gene and add another hundred or two to each het. They are in demand. Then you have the option to hold back any female hets to breed back to dad and grow out your collection adding new genes into clowns to either sell or hold back. Also may consider a backup male like an enchi clown or whatever you like so you don't put all of your eggs in one basket. This is basically how I started and am starting to build a quality collection.
Don't expect to make a return on any investment for some time. Females will take at least two years to get to size. Sometimes longer. With a quality male though you can put him to many females in a relatively short amount of time.
I should also add you should pick morphs you enjoy not just for the money. As for me that just happened to be clowns. Also for now I would just try breeding what you have and get a feel for breeding. Maybe invest into some quality equipment like a good incubator. Good equipment will give you better chances for successful clutches.
Also check out morphmarket you can use the filters and genetic calculator to get an idea of what you can produce with what you have or are considering and also see some current prices of what the morphs are selling for.
Hope this helps give you some ideas!
Sean