you can get a cheap pot lid shild at any stable or in the library at hyrule castle inside a hidden room you can find a royal guard shild

don't get the royal guard shield, bc as with the whole royal guard set, they "have a design flaw" which makes them break really fast. get the royal set instead, as that set provides the longest durability with the best attack power.

and anyway, you can get the hylian shield by defeating the stalnox in the lockup of hyrule castle. it's the best one in the game.