I'm pretty new to the investing game, so be gentle after reading this.
i must be poorer than i thought, if someone offered me $500 to drive 20 miles (not all day) i would do it in a heartbeat. sounds like your agent either doesn't really want to represent you or maybe not investors in general. if he had much experience working with investors i would've hoped he would have told you upfront about his issues with small commissions. In saying that, I agree with Ryan, you should have that conversation now and see if the partnership is fit to continue. if not then you have a heads up on what to cover with the next agent(s).
I am not an agent nor do i plan to get my licence any time soon. i assume you don't land every deal you try to make, no matter how hard you work for the investor. This should be a partnership so if the OP requested a viewing within the agreed area and the agent refused isn't that like an investor dropping an agent just because a deal didn't go through.
it all boils down to expectations. both sides need to lay them on the table, preferably in the beginning, but it's never too late. Most likely there will be compromise.
Redgy, maybe you should get your licence, if you were doing the leg work anyway shouldn't you get rewarded?