it shows GUI Shop 3 when i open the .json file and everytime i put the GUI Plugin inside my Server, it says all 1 and in the .json file the Prices i put in, even after i deletet the file

Do you have multiple guishop files on your server? if the file name says GUIShop_3.json then you just rename the file.. or delete all the duplicates and gen a new default one?  If you sent a screenshot so I could see what you are describing this would help a lot or add me on discord so we can get this sorted out quickly for you Khan#8615