Jonkincy

There may be a post on this already. If so please send me the link because I have not found it. I'm trying to place a setup fee (one time) on a product that is billed monthly. The closest I manage to do is make it an addon. But it gives the client the ability to choose to apply it. Configurable options would bill them every month for setup and that's not what I want either. Can an addon be automatically applied at time of purchase?