Good question. I don't have an answer but I'd be interested. I was put in touch with one by another writer once, but the agent only contacted me because the writer had requested it when, in fact, she wasn't actually interested in my scripts. Needless to say, it didn't pan out..
I'd say it is a tough sell to pay for just an introduction, perhaps if the agent or manager takes you on then it is a different discussion, especially if the manager is willing to work with you on your scripts to get them ready to send out to producers.