hi and welcome aboard...i would strongly suggest reading this thread regarding getting two as you wont know the sex till it reaches 7 months old at least and quarantining is a must with two of 90 days ideally in SEPARATE cages ...so i think one is best http://www.wineintro.com/forum/ubbthread...EGG_#Post161612
two WILL make it harder to have them bond to anyone...
keets are friendly to all they love their human flock mates AFTER they are completely perch...and hand trained...
save yourself some issues and get one and do not spare the pennies on a LARGE cage even for one bird as when you put in extra perches and toys your space or rather the birds will dwindle quick... or you will need to do as so many ...spend more getting a LARGE cage down the road....and remember bar spacing 1/2 in is the max ..width and height are important so the bigger and i do mean bigger ...the better...and id suggest getting a quality cage and all your things first...make sure cage is also coated wire for lead and metal toxicity issues
many of us use HAGEN VISION cages...this is a hagen vision cage and a great size...to give you a idea of how big it is for him (Cappy) INSIDE even with all the toys etc...you can find him on the bottom perch in there giggle if you look close
i believe petco maybe even petsmart now sells hagen vision cages but ebay usually has them cheaper even with shipping cost...so check our both places price wise...i got mine from ebay.
here is one on ebay now and its free shipping and the same cage viewed above...and you will never have to think of upgrading for any reason with this cage...and the coating more specifically even the wire under the coating is safer than any other cage out there...for metal toxicity issueshttp://www.ebay.com/itm/Hagen-83255-Visi...=item53e8963493
and the seller has a high reputation rating...smaller $50 cages are cheaply made...and these are what you usually find in most stores...and they are quite small