I have a thin 8yo son and I heard that the Old Navy “Karate” jeans in slim were the way to go. I just went to grab a pair and see that they are now only $17 (reg $30) + free shipping when you use promo code STYLE at checkout – SCORE!!! They are also available in regular and husky sizes too. (commissioned links)
P.S. That promo code works for 40% off almost everything at Old Navy (and Gap and Banana Republic too) and free shipping with your $25+ order, so you might want to see if there is anything else you “need”. Like maybe some jeans for mom too…
Shop the karate jeans here —-> http://shopstyle.it/l/S2Dq
Shop everything here —-> http://shopstyle.it/l/S2Dv