Don't forget about tired landlords, Zillow in the for sale by owner section w/out an agent and craigslist.

I suppose there is the aspect that the fee exists to cover some cost for folks who may be tire kickers who may never buy anything.

Just because I can buy a tire from Walmart doesn't mean I'll get the same service or products I'd get from my car dealership. 

The 9% response rate of yellow letters are all kinds of calls: curious calls, angry calls, tire-kickers, quality calls, etc.

If you found a tired landlord, they are pretty receptive to seller financing, they still want a monthly income just not the headaches and cleaning toilets.If you're flipping, then another option is to "partner" with the seller, buy an interest in the property using a TIC Agreement.

I am tired of starring good opportunities in the face and not being able to jump on them!

May not of been enough to put tires on the truck but it's something :-)

For every deal they do they've shown dozens if not hundreds of houses, listed properties that did not sell, dealt and dealt with endless tire kickers.  

Everyone gets tired of a property after a while and are willing to dump it so they can move on. 

They rarely bother you and are no where near "one flat tire away from missed rent".