I want to save up for an LV speedy bag?? Help?

I want to save up for a louis vuitton speedy 30 bag that has the classic lv monogram but it's a whopping $730. I am teen and i get about $20 a week. Do you have any tips on how I can save my money without getting discouraged for how long it would take? Are the louis vuitton bags really worth it? Will I get what i pay for?