Re: Can't afford to offer it for free...
Indeed. Stamp duty on buy to let is (for the sort of prices of most student properties) is 5% of the cost, that's money you'll never see again. There's usually a mortgage arrangement fee or other upfront charge from the lender around 1-2% of the loan value, legal transfer costs of another £1000 or so. Interest rates on buy to let are generally higher than residential, deposit requirement usually higher. Whilst individually the fees aren't big there's variable requirements to register as a landlord with local government, information commissioner registration, deposit protection scheme registration, plus inevitabilities like insurance and maintenance costs, plus electrical safety and gas safety certificates.
For someone who already has a buy to let property portfolio, then they'll know all that and factor it in, but the days when anyone could easily buy a property, let the sprog and a few mates rent it whilst at Uni, and sell on with a fairly secure profit are gone.