For RM0.99, you get a Plastic Bag, that's Guranteed for life. Yes, Tesco will replace it for free, forever!
It is a great way to encourage re-use, as this bag does last a few months of rugged use. I hope this policy doesn't force Tesco to go out of business.
PS- By the way, it's GOOD for the environment as well, besides being a 'value' buy. So do good for yourself, your conscience and for the environment, by using this bag. Thanks Syakir for pointing this out.