I use manual calipers $20-. The good thing about them is if your taking them accurately they are consistent.

I once bought a scale (Tenita I believe) which also measure body fat for about $100-. I ended up returning it. It was very inconsistent. There's too many variable to consider. Things that will throw those electronic measures off is: dehydration, food, if you've just worked out, time of day. Also, some of those scales ask if you're athletic do you do 10 hours of athletics per week? That means aerobic. Then they also say it will not be accurate if you life weights. They have 2 settings. Athletic or regular, and of course male or female. When I said I was athletic the reading was 9.5%, when I said not to athletic is was 19.5%.

Manual calipers all they measure is skinfold in milimeters, then compare it to a chart for men or women, then there's a sliding scale for age. The same pinch of fat in mm's for a 20 year old versus a 40 year old equate to about double the body fat.

For example, when I measure bf it's about 6-7 mm's on the calipers, I'm 40, so on the chart it reads 10.5%. A 20 year old with 6 -7 mm pinch equals probably about 5 or 6 percent.