Depends small ones propley about 60-70 big 5ft one probly 300-400 quid it all a ripp off tho i make mine

trust me lol iv recently brought one

I hate to say this, but it would depend on the type and size of your parrot. You don't want the bars so far apart that the bird can get their head through. Again, it would also depend on the size of the cage. The bigger you can offer, the better. Remember, birds live a long time, so it may be a very long term home for your bird and you want a master bedroom, not the small guest room. Next would be the brand of cage, quality, etc and of course, where you live. Me, I would have to have any commercial cage (fancy cage) shipped to me and that would be rather expensive. Small parakeet cages run about 45$ here, and so on up from there. pets question and answers,www.5d2d.com
However, the cage I have had my birds in for the past several years is quite large for cockatiels (abt 3ft x 3 ft x 18 inches). I bought it from Craigslist for about 40 $. I later purchased the parakeet size cage for $ 5 at a store close out sale (it had a tiny ding on one bar). I just use that cage for confinement if I need for some reason/transport/ or occasional visits to work/friends over the weekend. So look around before you buy and decide.
You said parrot, so you need to consider what type of cage is best for your bird. Some birds can easily bite through smaller bars, so that is a thought. I know several bird sites/catalogs, so only naming two here although there are many many others.
The two I know off the top of my head are "Drs. Foster and Smith" and the Birdtalk magazine. I get both and many cages are available for sale.

If you do buy a used cage, clean it very very well and maybe, if you can, let it air out, away from your bird, for a few days at least, just to prevent any bird germies from getting to your bird. Never know how clean the previous owner kept it.

Specify the size of your bird. My eclectus parrots (African Grey-Congo) size are in a 48"w x 36"depp x 72"tall This is about a $300-$500 cage

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