Training advice? Any ideas? I'm thinking of buying a punch bag?

Ok, I want to buy a punch bag to hang in my garage but I don't know anything about them. I do Kickboxing and I need one that wont swing around to much. Do any of you have any ideas on what type or make I should buy. I was thinking of buying an Everlast one is that good? I live in England, so English stores would help. Thank you in advance, Teresa.