Investors generally expect to pay up for quality. But that doesn't necessarily mean quality stocks are always priced at an appropriate premium. Every now and then, a worthy name goes "on sale" or suffers a full pullback by virtue of a stock's temporary lackluster performance.

With that as the backdrop, here's a rundown of three bargain stocks for promising companies that you can buy today at a below-average valuation. In no particular order...

1. If it's made of metal, Mueller Industries likely makes it

Mueller Industries (MLI -0.92%) isn't exactly a household name, but if it rings a bell, there's a reason. This is the parent company to several different machining and machinery subsidiaries like Tecumseh compressors, gas valve manufacturer Lincoln Brass Works, and Die-Mold Tool, which makes plastic injection molds. None of it is exciting. All of it, however, would be sorely missed if this equipment suddenly stopped being made.

Sale tag hanging on a grocery store shelf.

Image source: Getty Images.

The past few weeks haven't been particularly kind to shareholders, with the stock price still down nearly 9% from May's high despite last month's bounce. Like so many other names, investors became worried that renewed spread of the coronavirus via the delta variant would rattle Mueller operations; there's also a good chance shareholders have been doing a bit of profit-taking following a huge 166% run-up from last March's low.

Regardless, this pullback translates into an opportunity for anyone looking for an undervalued industrial stock pick. Shares are trading at 10.4 times this year's projected per-share profits, and although revenue growth will likely settle to a more typical 6% next year once the COVID-19 recovery has run its course, the company's bottom line is still expected to improve by 12% in 2022. That means this particular industrial name is valued at only 9.3 times its forward-looking profits.

Sometimes boring can be beautiful.

2. Lockheed Martin never really fights a cyclical headwind

While Mueller Industries isn't a mainstream name, Lockheed Martin (LMT 0.30%) certainly is. The $100 billion defense and aerospace contractor is the company behind the F-35 fighter jet, Sikorsky helicopters, and a variety of defense systems used by the U.S. Department of Defense and its allies. Lockheed Martin is even teaming up with General Motors to co-design a next-generation autonomous lunar rover for if or when we return to the moon.

The impressive pedigree hasn't prevented shares from dishing out a lackluster performance, short term as well as long term. The stock price is now down 8% from May's highs, capping off a 14% pullback from its pre-pandemic peak hit in February of last year. Nothing has impressed investors. In fact, last quarter's earnings miss only served to solidify the rationalizations for not allowing the stock to participate in the broad marketwide rebound from last March's lows.

But largely lost in the noise of political bickering, news coverage of the pandemic, and other issues is that the nation's defense budget not only continues to swell, but it is swelling in a way that disproportionally favors Lockheed Martin. President Joe Biden's original defense budget for the upcoming fiscal year was $716 billion, up slightly from the previous year's $704 billion, but last month the Senate Armed Services Committee added another $25 billion to the request, mostly to buy more hardware like fighter jets and ships. It's the one area where the two major political parties agree that the country can always spend at least a little more.

3. As the pandemic dust settles, Paccar is ready to roll

Finally, add Paccar (PCAR 2.58%) to your list of bargain stocks you can buy today.

Like Mueller Industries, Paccar is a vaguely familiar name, but it's difficult to say how or why. This will jog your memory: Kenworth and Peterbilt. Yes, Paccar is the parent to two of the biggest names in big-rig manufacturing. The company also does a bunch of other related work, like engine design, replacement parts, and truck-financing solutions.

It's a difficult business to get a bead on right now. Last year's top line slumped for the obvious reason, and while this year's worldwide economic recovery is driving huge demand for all sorts of goods, a shortage of truck drivers inherently crimps the need for new trucks: Who's going to drive them? 

On balance, though, there's more upside than downside ahead. Paccar topped revenue and earnings estimates last quarter, and analysts' consensus forecast calls for revenue growth of 32% this year versus last year's suppressed top line. This same crowd is calling for top-line growth of another 12% next year. That recovery should nearly double the company's per-share earnings during the two-year span in question.

Investors aren't feeling it yet, given how the stock price has peeled back more than 20% from February's high, reaching a new multi-month low on Monday of this week. But with the stock now priced at just 11.3 times next year's expected earnings of $7.08 per share, this pullback is looking like a juicy entry point. Bolstering the bullish case is the fact that analysts still contend the stock is worth $100 per share, up about 25% from the present price near $80.