So I got my last couple birds over the years from birdsnow. I try to avoid getting animals shipped to me- especially young ones- because sometimes they can revert on weaning. If you have no experience with hand feeding then you can always learn but parrotlets cost more than a pretty penny and it can be a daunting task.
I'd try to use birdsnow, craigslist, or any marketing forum to see if anyone close by is selling parrotlets that are either A)young or B)interacted with a lot.
It's cool and all when birds are handfed but being only held when getting fed doesn't really do much in building a bird's trust with humans (ie our hands). Get young birds from breeders that actually hang out with them.
Parrotlets aren't necessarily as aggressive as people like to label them but they do get nippy if unproperly socialized.