Should i use liquid foundation or powder for covering scars?

well i have a couple of acne scars on my face from picking them and i want 2 cover them with foundation i dont know what kind i should i use liquid or powder or just get concealer…also it my first time wearing make up i dont want to go all out and buy it i was hoping 2 go 2 my local beauty/hair supply store 2 get sum wuld that be ok or i shuld i just go 2 walmart(if so what is a brand for under 5 dollars) and is there any tips to find sumthing that looks like my skin tone and looks like i have none at all…..thanks i alot
p.s im 15 years young if your wondering