There are 25 factors that go into deciding whether or not which broker is the procurer of the sale. These are broken down based on the facts regarding the actions of the introducing broker and the closing broker. The burden would be most likely placed on the introducing broker to prove that their actions were the "procuring cause" of you writing an offer and buying the home.
Without an agreement and as a buyer, you can decide to use anyone you want. That is why so many Realtors end up demanding buyer-broker agreements because it only takes getting burnt once or twice on this issue to make the decision of not working for free. However, it is not clear to me from your post how much this other agent "worked". Did they only show that home, a couple of homes, 20 homes,... it gets down to the moral issue of how you deal with commissioned professionals and the specifics to your relationship with the 'introducing broker".
Honesty is the best policy for all. I would be up front with all the agents involved and hope that the transaction goes smoothly.
If you signed an exclusive buyer agency agreement you would be obligated, otherwise no. We don't get paid hourly, if I showed a property and someone else wrote the offer I would go after my commission.
This person wasted their time, gas, and may have turned down another job or customer to get you
to your property. The realtor probably did not only show you the property that you are speaking of
he or she probably showed you several and also spent time on the phone with you as well. If you signed
anything with them then you have to honor that contract. It sounds like you did not sign anything.
It is kind of like courting one person and then bringing home a brand new date in the middle of dinner.
On the other hand, if your realtor is really lame and you have a valid excuse for not using him, let them know
where they are falling short in an honest with them and if they don't comply then get someone else but at least give them a chance. They may have 7 kids to feed. I know that I do but that is personal and they never
would know that because we have a professional ethic to uphold. Give us a break!
If you go to an auto mechanic and they look at a car to decide what needs to be done to it, you pay them for the diagnosis! If you go to an attorney for advice, you pay them for their time. Why in the world do people feel that they can waste one professional's time, but would expect to pay another professional for theirs?
Sorry if this sounds like a rant, but I just see it happen so much! I don't understand what has happened to integrity in our society.