How to acheive “all-day” curls? And best straightener and curling iron?

My first day of eighth grade is in a month! =D I’m very excited, but I have a verrry big issue. My hair is naturally wavy, very limp, and thin. =/ Usually, for the first day, I straighten it.

This is where question number one and two come in: What is the best brand of cheap, ceramic straightener I can get while I save up for a Chi? Also, what is the best cheap, spiral (or tight barrel) curling iron I can get while saving up for the chi (I hear you can use it to curl, too)??

Anyway, this year I wanted to have my hair half up in a poof, and the rest down and curly.Since my hair is thin and limp, this is verrrry hard to do. Do you have any suggestions of how to keep the curls stiff and curly for the whole school day (or most of it, I could always put it up halfway through if its necessary)??

Thank you!!!!