CALLIPERS (Electronic)
Callipers can be very useful for measuring skinfold thickness and body fat estimations. While not 100% accurate (they are not going to give you your exact BF%), they can provide a very consistent and useful way of seeing if you are moving in the right direction relative to where you started.
PROTEIN
Whey protein is one of the cheaper forms of protein, but also the most useful. The Optimum Nutrition brand has been consistently ranked as one of the best, and is also one of the least expensive and best tasting protein powders.