You're going to need a food scale in order to count your calories and essentially to use this website. Food scales range in price from $25 to $100. I don't think you necessarily need an expensive one, you just need to make sure it has a few key features...

1. Grams and ounces

It should be able to display in increments of grams or 0.1 ounces. In other words, the resolution should be whole grams or tenths of ounces.

2. Tare function

The tare function is vital! It will be a real pain to measure out recipes without it. The tare function basically zeros out the scale, even when something is already on it. So if you put a bowl on the scale, and it reads 5 oz, you can hit the tare function and it will go to 0 oz and you can start measuring food you put in the bowl.

3. High max weight (10 lbs or higher)

The scale should have a high max weight so you can put pots, pans, blenders, etc. on it and still measure your food. For example, I frequently put my blender on it, hit the tare function, then measure out quantities of food directly in my blender. If the scale had a max weight of only 5 lbs, then I'd hit its max before measuring the food.