Ok, I just wanted to know and this is what I found out.

The Guinness World Records have claimed The Beatles have the biggest all-times sales for a band. This is based on an accumulative sales figure provided by their record company EMI who claim they have sold over a billion records by 1985.

Elvis' record company RCA Records claimed in 1981 that he had sold over one billion singles and albums, which would make him the biggest-selling solo artist of all time.