I don't live where you do so i can't tell you where to buy them, but i do know the prices.
it depends on the length.
12in ones that aren't great quality are $20 . better quality is $40
16in ones are $50 dollars and $80.
18in are $80 and $100
if you want indian hair, they can range from $200 and up. even 12 inch ones that are indian hair can be $200.