Rangers/Portsmouth

With sensible management that controls expenditure you don’t need a salary cap – just sound finacial management that runs a club like a business.

There is a very good example of it very close to home.

…and on a different spin to Garswood’s answer…you can’t have a salary cap unless it’s adhered to worldwide, otherwise you end up with one country paying silly salaries and all the best players going en mass there – similar to the IPL in cricket.