A Jackson helmet will be a lifetime item. The large window (4.5 x 5.25) ones run about $50. The flip force is adjustable.
The normal shade is 10. If you are learning and having trouble seeing try a 9. The other truck when learning is to weld with bright lights or sunshine on the work/weld site. You should be able to barely see what you are doing without striking an arc.
If you have the small lens helmet you can also get an ArcOne auto darkening lens as a replacement. These are nice lenses a lot of pipeline welders use with their pancake shields. No frills but they have a great reputation!