Where to get cardboard boxes for moving house?

Time to make use of my blog as a personal forum for information gathering again.

I shall be very busy over the next couple of months, renovating and moving house. I'm planning to do the packing and moving myself. So now my question is....

• where can I buy cardboard boxes to pack my stuff for moving house
• where is a good place I can donate old clothes, books and other things (PJ/KL area)

I would appreciate if anyone who has moved house can share their experience and tips.

Since, I am in the mood for asking questions, here's more....

We're moving from an apartment to a house. I'm concerned about the security aspects. In an apartment, you basically just have to worry about your front door. However in a house, theres the roof, the front door, gate and back yard etc. In terms of security, could those who are staying in houses share their thoughts on.....

• what we could do to protect the house from burglars?
• How do you guard your roof etc?

Any thoughts anyone? (On moving house and house security but firstly I would like to know where to find the cardboard boxes for moving house.) Thank you.