£180,000 I would buy approx 18 of these type of properties:
www.rightmove.co.uk/properties/114007025#/?channel=RES_BUY
Outgoings:
With a £10,000 deposit, and interest only mortgage (fixed for 5 years) the payment would be £50 per month = £600 a year
Incomings:
Rental would be approx £110 a week, so £5720 a year
Incomings - outgoings = 5720-600 = approx £5000 per property. Multiplied by 18 properties is equal to a £90,00 income each year.
(Why anyone would pay their mortgage whilst interest rates are so ridiculously low is beyond me).