from the consumer's point of view i'm sure we all agree that it's a practice we don't like. whether or not it's immoral would depend, in practical terms, on whether or not the overall cost of selling/staying in business has also gone up for the vendor in question.

every grocery store i've ever been to has been doing it for decades. it isn't as obvious now that it's all priced using labels on the shelves. but i can well remember picking up canned goods with stickers on top of sticker on top of stickers.

we need to remember ... business is business - even in charity thrift shops. it's unfair to generalize. tempting and very human ... but unfair.