I'm trying to do some exerxices in hebrew but i don't know when to use בּשביל or ל when i want to say "for".
It's a hard distinction to make. You can say both קָנִיתִי לְךָ אֶת־זֶה "I bought this for you" (= "I bought you this") or קָנִיתִי אֶת־זֶה בִּשְׁבִילְךָ "I bought this for you." I don't know what the distinction would really be, but they are often interchangeable.