Sage (typically white sage though there are other types that may also be used, and also rabbit tobacco by some Native American groups in other regions of the continent) can be ordered online, or found (if there is one) at a local occult store. I have found some very good prices on eBay, and some sellers on Amazon should frequently have it in stock -- not to mention many other occult sellers online.
Another thing to consider are banishing rituals.
If you follow a particular religious path, you can look for banishing rituals related directly to your religious beliefs, as to not step outside of your pantheon.
That said, there are many cleansing and banishing rituals out there, from meditations with visualization, to cleansing baths, and similar.
For some, ritual can very much help direct intent. If you can identify with, or relate to, Abrahamic entities, consider the Lesser Banishing Ritual of the Pentagram.
Others may well have good suggestions, and be able to direct better than I can.