British Airways has a new promotion for buying some Avios and getting maximum of 25% purchase bonus between February 10 and March 23, 2014.
The bonus Avios is 15% for buying 5,000 to 26,000 Avios and 25% for buying 27,000 Avios.
You can access this offer here.
The price of one Avios purchases at the 27,000 Avios level including the bonus is 2.23 cents each.
Iberia has separate offer for buying Avios and the bonus is tailored to your account (access here). My offer was 20% bonus and price per Avios 2.15 US cents (better than BA’s). You can transfer Avios between BA and Iberia account.
Whether it makes sense to purchase Avios, depends of your usage. They can make sense for short-haul flights between expensive city pairs.