I'm sorry if this has already been asked, but I was just wondering.
I'm trying to find one for under $30 that's actually good. The one I have now is about 25 years old, so although I like what it tells me, I'm pretty sure it isn't accurate.
I was also looking at reviews online and I haven't seen many for the ones in my price range, and the reviews I could find gave very low ratings.

Try going to Bed, Bath and Beyond. I just bought a scale there the other day, and they had a few different types on clearance for under $30. I bought the Thinner Portable Digital Precision scale (silver and black) for only $20, and it gives me the same weight as my $70 scale (taking into account the the more expensive scale weighs in .10 increments and the less expensive scale weighs in .5 increments), and I have tested the two against each other a number of times and am happy with the accuracy.

What I did to make sure I got an accurate scale is I weighed myself on the scale I already had at home and when I went to the store, I made sure to buy a scale that gave me the same weight. You might want to try that as well, find a scale that you trust (maybe go to GNC and use there "Have you checked your weight today" scale), weigh yourself right before you go to buy the scale and compare your weight on the actual (not the store model) scale you want to buy to see how close they are.

Many people that are not happy with their scale are dissatisfied because it weighs inconsistently, but if you weigh yourself in the store 3-5 times within 10 minutes or so, you should know if the scale is going to be accurate. Also note that you must put the scale on a totally flat surface and stand perfectly still with your arms straight down to get an accurate read.

Something else to note when you shop is how many "load cells" the scale has, in general, the more the better, but you still can get a good one that is a single load cell. My expensive one has a "multiple load cell system", but my $20 one is a single load cell.

If I were you, I would check out the $20 Thinner scale. If you want something that is more precise then .5 pound increments and/or want more than one load cell, you should check out the Weight Watchers Portable Precision Electronic Scale by Conair (if I remember correctly, the new version of this scale uses .2 increments), Thinner Digital Thin Scale, or the Thinner Glass and Chrome Digital Scale, all at BB and B. The last two are $40, but if you get a 20% off coupon, it brings it down to $32.