I want to make myself one of those super-cute cigar box purses, but I'm thinking I need to coat the finished product with something to keep it all nice (I want to decorate it with old ads or something like that). Any suggestions? Maybe like a polyurethane?

polyurethane's not bad - there's also a waterbased painteffects sealer that I use for mine; very clear and very waterproof and dries very quickly. not sure what brands you'd find where you are, but if you avoid asking for varnish and explain that you want to make a protective coating, the people at the hardware store will eventually understand....