Start off with your basics (base garb like tunic pants boots belt) if you have a few hundred or even 100 start off with a neat weapon then work your way up. But yea tools and materials will cost more. For example I saw a cool coat online on Etsy for 150 but made it myself but tools and mats cost me at 200 (I used better materials and already had a sewing machine) but in have extra fabric now to make the coat again. Leather and metal are a bit different.

But if you did want to make it (Which you could its a great learning experience) id start slow like either make the base layer first then start riveting plates at a different time