How do you mark your crochet/knitting rows?

[jaa]

I use different color thread also, but prefer small safety pins.

[Zenyatta]

I used a bobby pin out of desperation once, and now that's all I use.

[Judi Gums]

I like using bobby pins as they slid on and off easily with one hand.....and they are cheap and can be found in nearly every store, so I won't ever have to make a special trip just for them.

Judi G