If the Realtor has worked to put this deal together for you or with you, then they (as any commission based service provider) should be paid for their time and effort.
There are many ways the Realtor can get paid: (as I don't know exactly what arrangement you have with them)
~You can pay them for time and marketing effort.
~You can have the Realtor take their payment back as a note.
~You can allow them to take a percentage of their commission out of the upfront option consideration that the tenant/buyer has paid. (If their take is 6%....the Realtor gets 2% now and then 4% if/when the deal closes)
~You can give them the equivalent to one months lease payment upfront and then the total 6% commission at the close of the deal.
~You can offer them some of the monthly cash-flow (if there is any) throughout the entire length of the lease in addition to commission if/when it closes.
~They can be give ANY other consideration, such as a boat or usage of a boat, $1000 in Waffle House Gift Certificates, etc....etc. You are only limited to you and your Realtor's imagination.
It all depends on how creative you want to be and how flexible/willing the Realtor will be with his/her payment structure.
The issue is one of timing. And, as Wendy points out, it's also one of how much of an option fee can be obtained up front (that, in turn, is available to be passed along to the Realtor).
Three reasons Realtors generally don't like lease-options is that: (1) they may have to wait years for their commission, (2) the sale may never close, and (3) In the intervening years, the Realtor may change brokers (and the commission is actually owed to the broker, not to the agent). So, to ease those concerns, paying a Realtor up front for at least some of the commission will persuade more Realtors to assist with lease-options. Often it's done by using some of the option fee, but Darin lists a number of other good techniques.
Hope that helps.
Sylvia, Darin summed it up nicely. I'll simply expand a little on one of his points.
The issue isn't whether or not to pay an agent a commission; rather, the issues is WHEN to pay it. This is negotiable. Although one technically pays the commission via the proceeds at closing, lease-options present an interesting case depending upon how one structures them. Some investors will use a single closing, and others (myself included) prefer to use something similar to a double closing. Wendy Patton, a Realtor AND investor who specializes in lease-options, gives some recommendations, and I tend to operate in a similar fashion. Sometimes, she'll offer to front the entire commission (especially during a hot sellers market); other times she'll offer the agent a note for the commission (especially during a buyers market) that's payable upon closing. Occasionally, she'll also offer 1% (or so) upfront, and pay the rest at closing as Darin suggested. The point is that there's not a "one size fits all solution here".
Sometimes it has to come down to "thinking outside the box". I loke to make sure the realtor gets paid for their efforts upfront. To me it seems like a win/win to not make the realtor wait to get paid.