The scale I have is from Costco and it's a Health O Meter. It's not digital, but it's the same one as my doctor's office has. It's very accurate, and with a coupon they had at the time, I only paid $25 for it.
I have a Healthometer digital scale which weighs in .2 increments up to 330 lbs or 150 kg and has a memory for 2 people (I think, I threw the box out). If you use the memory function, it will tell you what you have lost or gained since the last time you weighed. This is a pretty simple scale, no BMI calculators or anything and it cost me around $25 at WalMart.
I have also known other people to get great deals on scales from ebay.