How can I buy...? Girls only please!?

I am 15 and really want to start wearing thongs. I hate wearing sweatpants and Soffe shorts because with regular underwear you can see a line. A thong would fix that problem. Plus some of my friend who wear thongs say they're really comfy. When i tried to pick out a really cute and not slutty thong, my mom got all mad and was like "Um, NO. When you do your own laundry you can buy that." So do you think that if i buy it and just put it in with the laundry kinda in the middle of the basket she'll notice it? Or should i just try to get her to let me wash my own undies?