I never buy anything on stalls as I simply cant be arsed looking through them all. Ive been looking for gold ore for the last few days, but searching 100 stalls is just horrible so i pick out about 20 random ones, forget where ive looked and give up. I actually usually just go round the stalls on the outside who put themselves in some clean air, as its stupidly congested in the middle of the marketplace. Its so hard to find what you are looking for, as unless the person has set the stall title as the particular item you want, then you literally need to click every stall to avoid missing out.
Stalls also do not promote healthy competition between sales prices, because by the time someone has actually found what they are looking for they are generally just happy to pay the price that is there rather than search through the other 50 stalls to see if its a little cheaper.
I dont ever have anything to sell as I give anything I get away, but if I did, I wouldnt set up a stall. Its not efficient to sell on your main character as its tied up in gameplay so you can only really trade when offline. Because of this, you have to make a noob char to do your bidding. Then you have to trade all items over and it just seems like a lot of hassle to do this every time you want to sell. I bet there are others feel this way and have stores full of stuff they could sell but cant be arsed with the hassle to make 500k, so in turn, buyers are not finding what they are looking for.
I know the GMs really like the stalls and sing the praises of the feature, but its flawed in so many ways. It is a unique feature and I thought it was great when I first saw it, ill grant them that - but I think its proven to be impractical and maybe they should just scrap it instead of being so stubborn and refusing to completely remove it, maybe because a lot of work was put into implementing the feature into the files and they have an emotional attachment? :P