Virgin America is offering a bonus on purchase of miles that gets progressively larger the more miles you buy, up to a 50% bonus.

This applies to purchases through January 31. The maximum points you can purchase in a year is 20,000.

Buying 20,000 miles nets a 10,000 mile bonus. That means you get 30,000 miles for $1040, or about 3.5 cents a mile.

The thing to remember is that Virgin America’s award chart is a bit different from legacy carriers, so in some ways that equates to buying miles from such other carriers for a bit over two pennies. I’m not a buyer at that price, but for topping off towards an award it’s a non-crazy price.

For instance, buying 30,000 miles is enough for a one-way San Francisco – London award in Upper Class on Virgin Atlantic, but that $1040 mileage purchase will need to be paired with $600 in taxes and fees.

It’s also two-thirds of the miles needed for a one-way business class award from Los Angeles to Australia on Virgin Australia.

Point purchases are processed by points.com, so to answer a common question about such transactions they do not post as travel or airfare to the credit card used for the purchase (and thus won’t earn applicable category bonuses).