I had a mail offering 5000 miles for taking out a Virgin Money
ISA or
Life Insurance.
There are Ts and Cs, minimum payments/qualifying terms etc so make sure you read those before you sign up.
I managed to get a lfe quote for £5 a month for minimum cover so 5000 miles for £15 (minimum 3 months premiums to qualify for miles)
£90 to buy 5000 miles through the website.