These are the RFS prices I am seeing - you need to have qualified for RFS by earning some Avios in the last 12 months as explained on BA.com
And the cash fare on this date in World Traveller (economy) is US$180, which isn't an unusual in that part of the world. So the best option is the RFS option for 5250 Avios, which I value at a UK penny each, thus £70, and a great use of Avios even in economy.