If there too expensive, or don't serve a purpose except to be popular, you'll have to offer to help pay for them. Maybe trade off with chores that you normally don't do.
Maybe say i'll scrath your back or something b ut wait a minute how much are they?
When you ask her make eyee conatct and give a smile.give her a good reason why you need the shoes such as they will last a long time so I won't have to het a new pair anytime soon.if she says no than don't start throwing a fit and imploring her to buy you them.ask her if you could help pay for half of it by doing chores.don't ask every day if she says no just give her time. Hope this helps... Happy holidays!-fire desire
Tell her nicely that you have no good shoes and that you really like those ones, and maybe say something like there's athletics tryouts or something and that you need shoes for it???
Based on my own experience with an extremely stubborn Mom (but I still love her), if she thinks they are too expensive, forget about those shoes and look for some that are cheaper.
You could ask her to buy them for you for Christmas, unless you are like I was and had asked my mom for about 100 things for Christmas.