A cold press juicer (another way of referring to a masticating juicer or triturating juicer) produces minimal heat while grinding fruits and vegetables into small pieces and extracting the juice. The action of grinding can access more nutrients in the fruits and veggies and the low heat ensures that those nutrients survive the juicing process without being overheated and compromised.
If, in addition to vitamins and minerals, you also want to preserve the dietary fiber that exists in many fruits and vegetables, you may also want to consider investing in a blender as an alternative for some occasions. A blender will create a thicker drink, which is great for making smoothies. Since it uses the whole fruit or vegetable, it will also preserve all the nutritional aspects of the ingredients you use.
Both juicers and blenders make great gadgets for healthier eating. However, the key to staying healthy is to keep at it. Hopefully the convenience and versatility of having a juicer around helps keep you motivated and equally excited about incorporating more fruits and veggies into your diet.