The best UK stocks to buy are not always the best businesses. Similarly, stocks may not be trading at the cheapest prices. Instead, the most profitable investments are stocks that combine these two traits – a great company at a very cheap price.

By considering such businesses for the long term, investors can open the door to impressive, market-beating returns. And given enough time, this tactic can even allow an investment to double in value. So if I had £5,000 to spare now, which UK company looks set to double in the future?

Unpopular and underappreciated

Finding quality at a low price isn’t always easy. Searching the financial media is often futile because too many other investors are finding the same companies pushing up their stock prices.

So when you’re looking for triple-digit returns, the best place to look is often where no one else is. That means venturing into the industries and sectors that most investors have fallen in love with. And right now, there are quite a few to choose from, including financial services, manufacturing, real estate, and electronics, among others.

In many cases, the UK stocks that were sold usually fell for a good reason. But for long-term investors, the trick is figuring out whether that reason was a frustrating short-term hiccup or a long-term catastrophe. If it’s the latter, then it probably makes sense to stay away. Otherwise, a buying opportunity may have arisen.

A chance to increase my yield?

Looking at the stock market, there are many businesses operating in unloved industries. And of all, Alpha Group International (LSE: ALPH) is currently catching my attention.

The firm has built its reputation as an expert in currency risk management services for small and medium-sized enterprises with international exposure. However, in the last two years, management has started diversifying its portfolio and subsequently transformed the company into a fintech alternative banking solution.

Despite operating in a highly competitive industry, Alpha has managed to carve out an impressive niche for itself. Subsequently, sales and earnings grew by an average of 34.4% and 29.4% respectively over the past five years. But that might just be the tip of the iceberg.

Recent reports from Allied Market Research and Grand View Research said that the foreign exchange risk management market, along with the alternative banking market, is set to grow by 17.5% and 19.3% respectively by 2030.

Even if Alpha does not continue to expand its current market share, these sector forecasts suggest that the company could be on track to double its business in the next four to five years. It’s quite encouraging because Alpha’s revenue has already increased by about 140% since my first investment in 2020. And since then, the share price has almost tripled!

Of course, long-term forecasts should always be taken with a grain of salt. And don’t forget that this part of the financial sector can be quite cyclical. So it may take a little longer than expected for Alpha Group’s share price to double (and it may never happen, of course).

However, with shares traded at a price-earnings ratio at just 9.8, the growth potential of this business seems to be being ignored by investors right now.