Although there was a time when the stock market was solely the playground of the wealthy, it no longer takes money to make money on Wall Street. The democratization of investing means even those with only a few dollars to spare can start building a retirement nest egg — and it won’t even cost you anything to buy and sell shares. The elimination of transaction fees has leveled the playing field for all.

So, if you only have a little money available and have already set aside enough for bills and emergencies, consider putting it to work for you today. These three stocks to buy with $500 are presenting crazy good opportunities right now.

AdTheorent Holding (ADTH)

We’re still figuring out all the ways artificial intelligence (AI) and machine learning can benefit our daily lives and workflows, but AdTheorent Holding (NASDAQ:ADTH) already discovered how to profitably apply them to advertisers and marketing agencies. 

AdTheorent avoids the problems of using personalized data by allowing machine learning and advanced data analytics to make programmatic digital advertising more effective and efficient at scale. Programmatic ads tend to be cheaper for advertisers because it is a self-serve platform that eliminates the need for salespeople to sell digital advertising directly. It’s a fast-growing opportunity.

According to Statista, programmatic ad spending will grow to $779 billion by 2028 from $545 billion last year. It still represents a small portion of the global advertising market. As more companies move away from using cookies and other individualized ad-targeting methods, the AI and ML techniques AdTheorent employs will become a necessity in reaching audiences. 

Revenue grew 2.8% in 2023 to $170.8million and ADTH forecasts it will grow at double-digit rates this year. Management is guiding adjusted earnings before interest, taxes, depreciation and amortization margins, otherwise known as EBITDA, to be between 20% and 25%.

XOMA (XOMA)

Royalty aggregator XOMA (NASDAQ:XOMA) is a unique way to cash in on the biotech space without the risk of drug research. Rather, XOMA looks for biotechs with early stage therapies that need financing to advance the treatments through clinical testing. It provides upfront capital in exchange for milestone payments and royalties down the road.

These aren’t just tiny biotechs looking for a hand. XOMA also has multibillion-dollar pharmaceutical giants like AstraZeneca (NASDAQ:AZN), Merck (NYSE:MRK) and Novartis (NYSE:NVS) as partners. With dozens of assets in its portfolio, XOMA has boosted its chances of more than a few becoming blockbuster drugs that pay off handsomely for it.

While revenue will fluctuate from year to year based on royalties received or milestones achieved, over time this will build up into a steady stream of income. XOMA started 2024 with the most cash available to it in the history of the company. In just two months of the current year, it began piling up more opportunities. 

Last month, for example, XOMA acquired an economic interest in the opioid Dsuvia, which has the Department of the Defense as its biggest customer. XOMA will receive all royalties and milestones from it until it reaches $20 million, after which it will receive 15% on commercial sales and 37.5% from DoD sales. It will also receive half of the $116.5 million in potential milestone payments due Dsuvia’s owner, Alora Pharmaceuticals.

XOMA stock is up 28% this year and should keep right on climbing.

Rigetti Computing (RGTI)

While its name sounds like something akin to banking at Fred’s Bank, Rigetti Computing (NASDAQ:RGTI) is really a quantum computing cutting-edge, technological wizard. It’s still a loss-producing tech stock at the moment, but it is beginning to rack up wins that could quickly turn the tide.

Quantum computing is an emerging technology. Its computers are designed to perform certain tasks much faster than traditional ones by harnessing the power of quantum mechanics. Where traditional computers divide data into binary 1’s and 0’s, quantum computers use quantum bits, or qubits, which put those digits into “superposition.” That means a 1 or a 0 can be a 1, a 0, both or an infinite number of possibilities in between — all at the same time.

Quantum computers have many potential real-world uses, despite not being very good at it yet. Rigetti, though, is taking a not-quite-ready-for-prime-time technology and bringing it forward. It recently deployed its 84-qubit Ankaa-2 quantum computer that improved error performance by 2.5 times compared to Rigetti’s previous QPUs. Rigetti also won a competition to develop and deliver a 24-qubit quantum computing system to the U.K.’s National Quantum Computing Centre.

At one point RGTI stock had doubled in value this year but now stands 6% higher than where it started 2024. Still, you can expect this tech stock to make quantum leaps going forward.

On the date of publication, Rich Duprey did not hold (either directly or indirectly) any positions in the securities mentioned in this article. The opinions expressed in this article are those of the writer, subject to the InvestorPlace.com Publishing Guidelines.