Through March 31, Alaska Airlines is offering a 30% bonus on purchased or gifted miles.
That reduces the purchase price from 2.75 cents per mile (plus tax and processing fee) down to just over 2.1 cents (plus same fees). Not worth it ‘as an investment’ or general miles accumulation strategy, you’d need at least double miles for that, but helpful nonetheless if you wanted to top off towards a first class partner award (say) on British Airways or Cathay Pacific.