Being honest, I think they are a waste of money. They draw attention to what you're doing - simply tuck a muslin cloth under the shoulder of your top, or wear a pretty scarf. Both cover you just as effectively without being a huge piece of fabric which is going to make people look to see what it is!
What Rock said - particularly if you have a baby like DS who screamed blue murder and flailed like a landed fish if I made any attempt to put any sort of cover over him whilst he fed.
I tried a blanket and a muslin, but he was only EVER happy when he was completely uncovered. He made such a fuss when I attempted to cover him that it made it far more obvious and the world saw far more boob simply because he was thrashing about so much.
No cover, slipped top up, latched him on, pulled top back down towards his face - nothing visible.
I agree with Rockchick. In the last year I have bfed discreetly here there and everywhere with the two tops method and when I see other people feeding in public I notice far far more when they have a big cover on - I think they do draw attention to what you are doing. If you want to try one anyway do look in TKMaxx - I often see the bebe au lait ones in there.
I got given one but it was the biggest faff and much more attention grabbing than a muslin and the vest top under normal top combo ( pull vest top down, normal top up, voila. Small boob envelope) . So I never used it and gave it away in the end.
I had a black bebe au lait one to be as discreet as poss (thought the colourful ones kind of defeated the purpose and brought even more attention to it) but lo got really hot under it, flailed about and it was generally unsuccessful, just used the vest and top option mentioned by pps.
I sometimes use a big scarf for getting DD latched on as she can be a bit fussy. I just tie two corners together and put it round my neck. the opening at the top is big enough to keep open so we can see each other. Most ofthe time we just do the 2 tops method but when its crowded the scarf is good.
I saw one of these for the first time a couple of months ago, when a friend whipped one out to feed her baby. It made it so much more obvious what she was doing and drew more attention to it, but then it gave her the confidence to feed in public so served it's purpose I guess.
While I completely agree that it's usually more discreet to feed without one, you never know what kind of baby you'll end up with. I know a couple of people whose babies were so easily distracted that the only way to keep them latched on in public was to use a cover. I prefer the two tops method myself, and have been known to drape a muslin occasionally if there's a lot going on. I say if you want to get one do, but if money's tight perhaps wait until the baby is born and see how you're getting on.
I never used a cover either; am happy wearing a stretchy vest top that I can pull down with bf bra to keep tummy covered and hoik t-shirt or top up to feed. My LOs are also the nosy type that don't like being covered. In situations where I want to be more discrete I just drape a muslin or scarf about me, more the illusion of more cover than actual cover, but really I don't think anyone can see anything anyway. Did not get on with those bf tops at all, the ones eg from jojomamambebe with the 'peep hole', just spent ages faffing to get the opening open & exposing more! So I recommended avoiding those!