stealing shit is bad!
But there's tons of ways to do it. No ink tags? No problem then. Realize that ALL security tags are, essentially, a thin metal pin that goes through the garment, with plastic/metal at either end, holding it all together. The hard part is walking out without setting off alarms. Once you're home, you have hours to get it off.
Now, you basically need a decent set of wire cutters. It's easiest to use and has the least potential to do damage to the item you just..ahem...uh...bought.
Security tags have two ends: the end with a little bit of plastic and a pin in it, and the end with more plastic, the thing that sets off the sensor, and a hole to accept the pin. They all work on a magnetic basis, so if you fucked around with a strong enough magnet...
Or you can just hack it off with the wire cutters. Can't you google a tutorial on this?