Do get disappointed or irritated with SAHARA flash disk behaviour

Sahara flash are common in the market and are very affordable if not cheap to say, one of the problem I have experience with them is that they don't last, You buy one and get spoilt within a week or a day, or is it that some are substandard but we use them still. Lately I bought one and guese what after saving to half way of the disc capacity all my data are gone, frankly speaking I get dissappointed whatt can i do or which is the best flash disc outside there