What hair vitamin should I take?

I used to blow dry and straighten my everyday for school (ik it's bad!) to recover this summer I'm not using heat and I got my hair trimmed and got a treatment on it. I also bought 3 new conditioning shampoos and conditioners. I also have thin hair with lots of layers. I need one that will thicken it and make it stronger&healthier and hopefully make it grow! And I need one sold at Walmart :) Thank you!