|My 7" Tool Kit|
1. Short, very sharp scissors. Mine are Westcott, 5 inches long. They will not let me take them on planes. I can live with this.
2. Cloth tape measure. It will measure any shape and size from glove fingers to a blanket. And you're under no obligation to share your measurements with anyone you don't want to.
3. A needle sizer/gauge finder. Really, though you may think you don't need one, when you do nothing else will do.
4. Flexible stitch markers. Again, it's one of those "when you need it you need it" deals. Don't plan to throw it in the bag when you think you might, just always bring them.
5. Locking stitch markers. See 4 above.
6. A good tapestry needle. They are for more than finishing and weaving ends. Plus, they're one of those things somebody always needs, so you can loan it to a friend for a minute, and feel very competent.
7. A small to mid sized crochet hook. They're the easiest way to pick up dropped stitches. I carry the 3.25 inch Lantern Moon one, and it will do the job up to bulky yarn. Above that, I would need a bigger one.
8. A bigger crochet hook. It does all that the little one won't. (And in a pinch it's a coffee stirrer. I'm just saying...)
9. A row counter. When knitting in public, it's much harder to keep these numbers in your head. Plus, they're generally cute and tiny, so you have no real excuse.
Isn't all that stuff expensive? No. Maybe $2 at a yard sale, $6 on eBay, and $20 if you get it all new. (Clover sells a kit with most of these things for under $10 at most North American craft stores.) If you're at a point in your knitting life where you can afford luxury, you're still going to have trouble spending more than $50 on the very fanciest stuff you can find.
Build your tool kit. One dozen tools will make your knitting on the go as comfortable as knitting at home. Put it all in a pouch so it doesn't get lost in the bottom of the bag. :)