If you can fit in them, Goodnites are usually a decent starting point for most DLs, provided you're alright with pull-ups. You can't really rely on them for anything more than small, controlled uses, but they're decent and easily available. Barring that, Depends with tabs are the best you'll get in most stores, but I've heard their quality (what little of it they had compared to most adult diapers) tanked when they ditched plastic for cloth backing. I think Walgreens and CVS have their own brands that might be good. Drug stores might carry Tena, Attends, Abena, or other good medical brands, and I've heard of premium AB/DL diapers showing up as well. Thrift stores/Goodwill might have a pack of good diapers, but its pretty rare. So those are your main options.