Fellow Fool writer W.D. Crotty thinks Dollar Tree (NASDAQ:DLTR) may be passing the buck when it blames high gas prices as the reason for lower same-store sales. Take a look at declining comps from competitors Family Dollar (NYSE:FDO) and 99 Cents Only (NYSE:NDN), and you start to believe that oil is indeed the culprit.

But if consumers are tightening their wallets, it seems to me that these types of value-focused retailers would be the ones that buyers flock to. Perhaps as testament, penny-pinchers weren't running from Dollar General (NYSE:DG). Fresh off of the heels of strong July comps, Dollar General reported equally impressive second-quarter results.

Net sales rose by a stout 12.5% compared with the same period a year ago, a show of strength that the company attributed to new stores as well as to 3.9% growth in revenues from units opened more than a year.

Gas prices didn't dampen its sales, but increased transportation costs did have an effect on gross profits. Dollar General identified those costs as one of the reasons its gross profit margins declined to 28.6%, versus 29.2% from the year-ago period.

The company was able to offset the hit to its gross profits by decreasing its selling, general, and administrative expenses as a percentage of revenues. It also cited a reduction in store labor costs.

The end result was a 6% net earnings growth to $75.6 million. Through the first six months in fiscal 2005, Dollar General has earned $0.43 per share, with expectations to earn an additional $0.72 to $0.76 per share through the remainder of the year.

Given its sales and earnings growth, in addition to its rapid store growth with plans to open 730 new units this fiscal year, Dollar General supports a reasonable valuation at 16 times current-year earnings. Investors might do well to pass up the struggling competition, but Dollar General's successes are worth a salute -- and a closer look.

For more on the competition, check out these articles:

Fool contributor Jeremy MacNealy does not own shares in any of the companies mentioned.