Obligations to agent that showed me property?

[Dan Lee]

Hello Bp, 

Looking for your opinion on whether I am obligated to go through an agent that showed me a property or if i can go directly to the listing agent. 

I am a contractor that flips homes and real estate investing on the side. I have pretty good knowledge of my local market and when something comes up that I like, I generally seek out the listing agent and contact them directly for the sale, etc. A few weeks ago I went to look at a small multi-family property and in talking to the listing agent he convinced me to let him show me a property that needed work in a pretty "hot" area of town. 

The property has been listed for about 120 days. Originally asking price was $599,000. They have dropped the asking price down to $499,000. Looking at comps and being conservative I think I could get around $590,000 when finished. 

After the showing I did a estimate and the house needs close to $100,000 in work. I told the realtor I would be interested in looking at it again to do a more detailed estimate but I did not want to waste my time or the agents since my max price with that much work needed would have to be around $420,000 and was wondering if he thinks if the seller would go that low. 

Since that email I got no response from the realtor (Its a little annoying at least respond saying its too low). I think my offer is reasonable given the amount of work needs to go into the property. Can I contact the listing agent directly with this offer or am I somehow obligated to go through the agent that showed me the property? 

Thanks guys!