depends on whether you have vinyl or leather bags... i have several products for each, but my preference is vinylex for vinyl and townsends for leather- you can use just one product for vinyl, but leather prefers a separate cleaner from protectant.
I haven't had to use a cleaner on bags for ages...generally just wipe them off. Have a bottle of Lexol handy for that purpose, as we also use it on car leather.
For general protectant, I use the HD Leather Protectant, the stuff that kinda looks like Vaseline. I apply the stuff fairly generously, and come back a few hours or a day later and just wipe off any excess. Does the job really well as far as I'm concerned, and is inexpensive.