Tea lights set in mason jars: I like this idea combined with frosted mason jars which is just a simple spray can. Place multiple jars at each table. We can get mason jars of all differing sizes at Goodwills in the area.
Hanging lights on branches. Go natural with a fat branch and hang a combination of ornaments and candles attached with wire. Use twine or strong fishing wire to suspend the branch from above. You might want to try hangers so as not to damage your ceiling.