The asset limit for full aged pension is just over $200,000.
The income limit is $200 a fortnight for a couple.
So if they buy a $70,000 property they fit under the asset limit, the deemed income would be a problem though on the remaining $200,000.
Pinched from Centrelinks web pages -
From 1 July 2002:
if you are a member of a couple and
at least one of you is getting a pension, the first $57 400 (combined) of your and your partner's financial investments deemed to earn income at 2.5% per annum and any amount over that is deemed to earn income at 4% per annum;
Insurance bonds were a way of reducing your deemed income but that loophole seems to have closed now for new players.
Some f/p offer services to maximise pension benifits, not sure how they can do it now
Of course if they earn better than the deeming rate that is bonus cash for them and they can claim franking credits without having to lodge a full tax return