Our system allows for two rent rates. A main ongoing rental rate for those intending to buy which includes something towards the option value in the deal.
Additionally optionally if you want to give buyer a chance to check out the place for a while at modest cost you can set an initial discounted rent for a period, say a day or a week or a month.
The main rent should be normally be set high to encourage the buyers to complete on the sale or go elsewhere. Unless you are happy with it turning into a long term rental in which case you may set the rate to something more reasonable.
So say you've got a flat in london worth £1m or so. You might set a low rent of say £100/day for a week for buyers to check it out at something comparable with hotel rooms and then an ongoing rent with option to buy of £500/day which would only really make sense if they are going to buy rather than rent. It would then cost about £15k to the buyers if they drop out after a month say.
Some of the higher rent may be waived at Equigudges discretion if the seller has materially misrepresented the property - say the lease length if wrong or there are major undisclosed problems that could not be seem on day one. If there are problems apparent on day one like scuffs or the heating does not work then the buyers should pull out then and just pay rent for a day or two.