There are many different ways to mark your stitch:
|Makeshift stitch markers|
-Short piece of strap yarn, preferably of a different colour so it's easier to see
See an explanation of how to place your yarn as a stitch marker (which in this case, doubles up as a row marker too!)
|Source: Clover USA|
-Plastic stitch markers: make sure you buy the ones that can open or split, or else your marker will be crocheted in.
|Source: jeanettejed on Etsy|
With just a few bits like beads and wire, or recycled lobster claw clasp from old bracelets you don't wear anymore, you can create your own stitch marker. Here are different websites with instructions:
-C.W.Frosting handmade stitch marker tutorial (also includes instructions on how to make beads from a torn magazine page. Nice!)
-Dollar store crafts (make sure you follow the crochet marker instructions, not the ones for knitting)
I just use yarn, 'cause it's light and not in the way, but it's fun to make your own stuff sometimes.