I got some replacement fans a couple of weeks ago for my XFX RX580 GTS for €17,75 (abt US$20) and they work great.
On aliexpress, these fans cost $ 7-8. The only problem is the quality of these fans, because they break down within 6 months.
If there are good quality fans in your country, OK.
But the original fans were installed to me only after contacting an authorized service center.
Where I live got the fans within 2 days from amazon, AliExpress would have probably taken 2 to 89 weeks. Sofar working fine, how long they will last don't know.
Did the replacing myself was dead easy had to disasemble it completely ( abt. 8 screws) and repaste at the same time. Those XFX cards are really easy to take apart.
I started having problems after 3 months, and after 6 months I threw out most of those fans.
I hope you are more fortunate, because you will find out about the quality of the fans in a few months.
Quality of these fans remains to be seen but that is with most thing. You can collect your brand new car from the garage drive away and have a breakdown about a hundred meters away so quality doesn't say everything and by the the way I wish all who read this A Very Good And Properous New Year