Be extremely careful as I can assure you rent or lease to own is more often than not a sure fire way to get taken advantage of. See the article I've linked below. There are certainly hard money investors out there but you should expect to have to pay roughly a 2% origination fee and 12% interest (at least that's the going rate in our area) and this is likely to end up badly.... more
I need more information.... did you sign a contract to sell your home to a buyer and then changed your mind? If that's the case, you are very lucky $300 is all you are being hit with. Did the buyer mutually agree to cancel the purchase contract?
I let sellers out of my listing contract free of charge if they aren't happy.... up until the time they sign an agreement to sell the home (purchase contract/accepted offer). At that point I fulfilled my end of the bargain and that is what I get paid for. If they want to cancel before we find a buyer.... then that's all good - and I'll help them next time around.
Another thought... have you just not found the right home? Is the same agent helping you with that side? If you had a strong offer, maybe you can extend out the time on the deal - to give you additional time to find a home?