We've considered a very small free plan, and will think more on that. As per the rent collection for these accounts, it doesn't become profitable for us at these smaller numbers, so this is why the $9 plan exists.
Are you thinking of making this internationally available? The whole concept of 'rent collecting' and 'checks' or 'paying rent is cash' doesn't exist in Europe. Rents are paid by bank transfer, usually automated (with rental contracts stipulating that the tenant needs to set up this automatic transfer or otherwise there will be a rent hike).
Re: pricing, I agree that a smaller or freemium plan would be nice, but for people who don't need anything from you to do automatic collections (i.e., everybody outside of the US ;) ), it would be quite hard to see how you could make money off them.
