My most essential things are my tiny pair of scissors and my seam ripper! The scissors are really tiny enough to use for seam ripping, but I'm afraid of cutting the fabric. I always make sure they both are close at hand. I also keep a lintroller nearby to grab little pieces of thread. Lol. These things probably didn't cost 10 dollars all together!
SittingPretty--I have a pair of hemostats always! If y'all know anyone who works in a hospital or clinic--I'm sure you can get a free pair! If a surgical kit is opened here, whatever isn't used is tossed, so they are easy to come by. I'm always losing a drawstring into the waistband and they are great for retrieval! I need to pick up another set to keep by my machine for pulling up the loop of thread.