I'm a cheap ***, so I got a couple cheap digital scales to try out. The first was $6 on sale from ~$30 and was a total disaster. It broke within a few weeks and would skip tenths of a grain.
The scale I have now (in addition to a Lee and a Lyman 505) was $23 shipped. Goes to 20g (~300gr). I have compared it to a $1500 (that was a loooong time ago) Ohaus laboratory scale at work. Put it this way... it would require a $500 check weight to determine which one is more accurate. I will stop short of saying that they are "accurate" to 0.02gr, but they are more than good enough for reloading.
Beware of scales that are accurate to 0.01g. There is a conversion error when going to grains, and sometimes they skip a tenth. A good portion of scales sold as "reloading" scales can't always resolve to 0.1gr.
Here's one example (since Nick mentioned it): http://www.brianenos.com/store/be.scale.html
1543.4 grains 0.1 grains
100.00 grams 0.01 grams
It might be accurate to 0.01g and read out to 0.1gr, but it can not have 0.1gr resolution, so it can be no more accurate than 0.2gr. (see chart below)
My first digital scale was prone to this and was frustrating. What if I want 8.7gr or 9.5gr? Cant' get there. You need at least 0.005g resolution to be able to round to the nearest 0.1gr. 0.005g accuracy will resolve to ~0.04gr (probably good enough for consistent charges to 0.1gr). 0.001g accuracy will resolve to ~0.02gr. If someone has the Brian Enos scale and can demonstrate differently, I'd like to know, because otherwise it looks nice.
1 gram = 15.432358 grains
grams grains rounded off
0.50 7.7162 7.7
0.51 7.8705 7.9
0.52 8.0248 8.0
0.53 8.1791 8.2
0.54 8.3335 8.3
0.55 8.4878 8.5
0.56 8.6421 8.6
0.57 8.7964 8.8
0.58 8.9508 9.0
0.59 9.1051 9.1
0.60 9.2594 9.3
0.61 9.4137 9.4
0.62 9.5681 9.6
0.63 9.7224 9.7
0.64 9.8767 9.9
0.65 10.0310 10.0
0.66 10.1854 10.2
0.67 10.3397 10.3
0.68 10.4940 10.5
0.69 10.6483 10.6
Here's my scale: DealExtreme: http://www.dealextreme.com/details.dx/sku.10515
I've had it and been using it for about a year, so far so good. The tray is too small for my powder pan, though, so I have to work around it.
FWIW, my scale is identical to the $80 American Weigh scale.
I'm not trying to sell anyone on it, I merely set out to prove/disprove the notion that cheap Chinese scales are total junk. There are better scales out there, but at several times the price. These for instance:
The second one has 0.002g resolution which will resolve to ~0.03gr, and is a good buy IMO at $122, Plus it has 100g capacity (>1500gr), so it will weigh just about any bullet out there.
ETA: oops, sale's over it's back up to $167.