Track Shorts

I have been wanting these athletic shorts for some time now and still haven't gotten them... My mom is waiting for pay day which is like a week away and I only have jean shorts and that is so not good for summer cuz of the heat. They stick to you and you can't get 'em off! Ugh! I really need these but she doesn't want to pay $20 for them. Is that the normal price, or am I looking at places with too high of prices??? I'm looking at Justice, Adidas, Academy, and Target. If you know anywhere cheaper, please tell me in a comment! Thanks!!!
~Ally
P.S.- Here's a photo of what I am looking for!