Depends on the kind of conda you want. As was said yellows stay relatively small.. however I knew one female that was 12' and about 70+ lbs.

My male is around 7' or so. I have three yellows.. they all bite.

Greens get a lot bigger. Males 8-10' females.. watch out. Greens are the heaviest snake species in the world.

My male is only around 4-5' now.. he's pretty well behaved, but he has bitten too. It's a conda thing.