
5 DVDs at 49¢ each + 1 DVD at $14.95 = $17.40 up front
4 DVDs at regular club prices of $23 each = $92 over 2 years
Thats a total cost of about $109.40 for 10 movies or around $11 per DVD.

For comparison I looked over at Amazon and checked the cost of some popular DVD movies. The Departed was $13.49, Iron Man was $16.99 and Spiderman 3 was $13.49
So the DVDs on Amazon are typically around $13.5 to $17 each. I am not including shipping on the Amazon DVDs since generally their DVDs qualify for free shipping with orders over $25 so you could get free shipping if you by 2 DVDs at a time.
If you joined Columbia House DVD club as a new member then you would save about $25 on the purchase of 10 DVDs compared to buying them on Amazon.
In my opinion it is certainly a good deal to sign up for Columbia House as long as you're pretty sure you'd buy at least 10 DVDs over the next 2 years.