Pionus have a reputation for being quiet, gentle, easy birds but
this is only in comparison to other parrots. They are capable of making calls that make your ears ring and their bites will draw blood if they mean it! They are closely related to Amazon parrots and need to be treated with respect. They generally prefer to be around people and to watch what's going on, but don't necessarily want to be in the middle of the action.
A well-raised Pionus will give you a series of escalating warnings before biting: they will lean away from you, shuffle away, lunge at you with their beak open, give you a hard beaking and, if you've somehow failed to get the message, only then will they bite with intent. They are intelligent birds and like to be given the time and space to make their own minds up about something. If you try to force a Pionus to do something they want to do, you get what you deserve!
They tend to be soft-beaked and prefer softer materials to chew: balsa, basswood, cork, palm leaves, cardboard, paper, lolly sticks, loofah, wicker and thin slices of cross-cut pine. Toys that are made on hardwood or bamboo tend not to hold their interest. Some Pionus like shiny stainless steel toys to rattle and bang about.
Cage size information:
Wingspan Info | Natural Inspirations Parrot cages
For a Pionus, you're looking at a cage of around 100x80 cm/40x30 inches. Bigger is better but make sure that the bar spacing is small enough.
When you say "free-flying", do you mean outside? Pionus are not big enough to do that safely: at around 200-260g (depending on species), they are around 2/3 of the size of a feral pigeon, and therefore ideal prey for many species of falcon and hawk. I live in London and we have sparrowhawks, buzzards and peregrine falcons so don't assume that your area is free of predators.
However, Pionus are skilled flyers and will enjoy being able to fly around your home. Set up multiple stands, perches and play areas and teach your bird to station. Like other parrots, inactive Pionus are prone to heart disease so encourage them to be active and move around. I target train my girls and ask them to fly across the room to touch the target.
I have no idea what country you're in so cannot tell you where to get one.