Last season I bought a pair of Rock Star jeggings in a dark wash and loved it so much I kept it even though it was at its original price ($34 I think). I also picked up another pair in store on super sale and loved it. See it on me in this post and this post. I haven't tried on the Rock Star super skinny jeans before, and I'm not even sure if they are different from the jeggings, or the same with a different name, but you can see them on Tiffany here. There are 12 colors to choose from. They all come in regular, petite, and tall sizes. Notice also that if you chose regular, it also gives you an inseam of short, regular, and long. That's a great option for me. I ordered the petite 0 before and found it too tight on the waist. Petite 2 is too loose all around. When I finally chose the regular 0 in short inseam, it fit perfectly. So if you are not sure, order different sizes to try. Return is quite simple for Old Navy online purchases. Just go to your nearest store and they'll take them back.
All Rock Star jeans are on sale now for $19, with still many sizes available. Use code ONCARD20 to get 20% off $50 + order with Old Navy Card. (That's $15.2 total after all said and done.)
If you don't have an old navy card, try use ONEXTRA15 to get 15% off any order. I haven't tried the second code, so please let me know if it works if you do end up ordering. Rock Star jeans excluded.