Anybody thinking they are not going to need a flash for macro has a learning curve. Or they are only shooting inanimate objects with a tripod.
Sure there are good macro photographers that use natural light, but I'll bet they started with flash (actually multiple flashes).
At minimum I would start with a 1:1 lens, a set of extension tubes, a flash bracket, a flash (at least a 400 series or more powerful, or two flashes) and a diffuser (these can be home-made, but are not so expensive either). Inexpensive macro lenses are likely to still be very sharp, it's the features and focal lengths that make them more expensive. I can't off hand think of a 'poor' macro lens.
And as with all types of photography don't expect great results without a lot of practice.