What purchases do you think are good from Dollar Nail Art and what are bad? I've heard the foils are difficult to maintain, and I was wondering if you knew of any other nail arts to avoid.
In my own honest opinion, I would only use that site to purchase foils - my main reason being that they sell them at the cheapest price I have seen and they give free adhesive.
I would not consider the other items "bad," but I also would not purchase them there. Although the items are only a dollar, you don't really get much. I bought three rolls of striping tape from the site ($1/roll) and I also bought some on eBay to compare. They were exactly the same products, but on eBay, I got 10 rolls for $1.26 (yes, $1.26 for all 10 rolls, free shipping, no tax). This is also the case for rhinestones, glitters, and studs. If cost isn't a problem to you, then nothing on the site is "bad." The items are all very high in quality.
Now, regarding the foils, yes, they are difficult to maintain without a top coat (of course you should always finish off any manicure with a top coat, but the foils crinkle up and lose their chrome finish). They fall/chip off VERY easily if you plan on using your hands after (lol). I was able to keep a manicure of foils (see my rose manicure) for a bit over a week, but only because I applied a top coat. The rose and snake skin foils do not crinkle up as much as the chrome foils, so I would definitely buy those again.
Overall, I would still suggest you to purchase any item off the site. They're different and just plain fun to experiment with. Good luck! :)