The biggest retail trend happening right now is telling us one thing – we’re getting cheaper.

The growth of dollar stores and other value retailers has been among the few success stories in retail in the last few years, charting the most growth in the sector and absorbing a lot of empty space vacated by more traditional companies that didn’t make it.

Nationally, the top dollar stores are expected to surpass $50 billion in sales by 2015, according to a new report by web-based retail research firm myRetailPOV – a staggering number for companies that pride themselves on rock-bottom prices.

In Eastern Massachusetts, the biggest bargain merchant success story has been Dollar Tree. In March 2010, the company had 43 locations in Eastern Massachusetts. Today, they have grown to 56.

"Dollar Tree’s store growth in this case came largely from moving into vacant units," said Robert Sheehan, vice president of research for Burlington-based KeyPoint Partners, a retail research and real estate services firm. "Value retailers are showing substantial expansion, like Ocean State Job Lot and Big Lots. Even when you move into more moderate to higher-end specialty store retailing, a large segment of their growth has been a result of outlet stores. Shoppers are looking for more value than prior to the recession."

In the near term, expect to see even more Ocean States and Dollar Trees popping up in strip malls near you, Sheehan said. But, he added, when the economy finally strengthens, "a lot more traditional types of retailers will be growing as well."