Dark armpits? *ten points!*?

Okay, so I am really self conscious about my arm pits. I am African American so therefore, I have dark hair. I shave my armpits about once a week(it doesn't matter if I shave more or less) but after I shave, I still she darkness. I looks so disgusting!; like my armpits are covered in hair. SO summer is coming and I'm so self conscious of my arm pits and I can't wear tank tops, and even for graduation! because i'm wearing something sleeveless. so what could help to lighten that? or just stop that all together. please don't suggest laser hair removal or anything expensive. i'm only 13. Thank you! I'll give points!