A mountain bike, originally priced at $650, is on sale for 20% off.
After the fixed shipping cost of $25 is added to the new price,
what is the final cost of the bike?
The discount amount is 20% of $650, which is (20/100) * $650 = $<<20/100*650=130>>130.
So, the bike is now priced at $650 - $130 = $<<650-130=520>>520.
After adding the fixed shipping cost of $25, the final cost of the bike is $520 + $25 = $<<520+25=545>>545. Answer: \boxed{545}.