You don't need to have the bank account of Warren Buffett to begin investing in stocks. Nor do you need to invest solely in companies with ultra-high stock prices like Amazon, which is trading at roughly $3,629 a share as of this writing. Investing on a budget can be profitable, too, and there are plenty of strong companies with share prices that are much more affordable.

In that spirit, here are two stocks worth buying that trade for less than $100 a share: AstraZeneca (NASDAQ:AZN) and Incyte (NASDAQ:INCY).

The case for AstraZeneca

AstraZeneca may not have made as big a dent in the coronavirus vaccine market as it hoped to, but in my view, the company's growth opportunities lie elsewhere anyway. The drugmaker boasts a slate of treatments with fast-growing sales, some of which are in its oncology segment. The field of cancer medicine is both the largest and one of the fastest-growing in the pharmaceutical industry -- spending on such treatments is expected to grow at a compound annual rate of between 9% and 12% through 2025, according to some estimates.

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AstraZeneca's oncology division sales increased by 20% year over year to roughly $3 billion in the first quarter. Among its top cancer drugs are Tagrisso, Imfinzi, and Lynparza. Sales of Tagrisso increased by 17% to $1.1 billion in the first quarter, revenue from Imfinzi popped by 20% to $556 million, and Lynparza's sales came in at $543 million, 37% higher than the year-ago period.

What's more, the patents on two of those three medicines (Tagrisso and Imfinzi) won't expire until the early 2030s. Investors can expect many more years of revenue growth from these drugs, which will likely be bolstered by label expansions, as both are still being investigated in clinical trials for new indications. (Imfinzi in particular features in well over a dozen ongoing studies).

Another area of growth for AstraZeneca will be rare diseases, especially following its $39 billion acquisition of Alexion Pharmaceuticals, which closed on July 21. Alexion's two best-selling products -- Soliris and Ultomiris -- are the only approved treatments for the rare blood disorders paroxysmal nocturnal hemoglobinuria (PNH) and atypical hemolytic uremic syndrome (aHUS).

Alexion has also been building up its pipeline of treatment candidates in recent years. Last year, the company's management said it expected 10 potential product launches by 2023. This all bodes well for AstraZeneca's future, as it will likely see a slew of new drug approvals in the next couple of years that will meaningfully contribute to its top line for many years to come. (AstraZeneca had dozens of pipeline programs of its own even before the acquisition.)

Thanks to all these factors, this healthcare giant looks like an excellent stock to buy and forget. 

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The case for Incyte

Incyte's stock price is down by 25.2% in the past year, while the S&P 500 is up by 35.9%. That poor performance isn't too surprising for at least two reasons. First, the company's shares were richly valued just about a year ago. Second, investors seem to be increasingly turned off by the fact that Incyte's revenue stream isn't diversified. It generates the bulk of its sales from Jakafi, a treatment for myelofibrosis and polycythemia vera (both are bone-marrow diseases), and steroid-refractory acute graft-versus-host disease (GVHD), which is an adverse immune response that can follow a stem cell transplant.

Approved by the Food and Drug Administration back in May 2019, Jakafi remains the only treatment on the market for steroid-refractory GVHD. In the first quarter, Incyte reported total revenue of $605 million, up 6% compared to the first quarter of 2020. Jakafi's revenue came in at $466 million, a mere 1% increase compared to the year-ago period. However, there is more to the story. During the first quarter of 2020, sales of Jakafi got a short-term boost as healthcare providers moved some of their purchases forward due to concerns regarding COVID-19 restrictions.

This lone product continues to provide more than 70% of Incyte's revenue, but here's why investors shouldn't be too worried. First, sales of Jakafi -- both within its current indications and from potential label expansions -- will likely continue to grow for the next half a decade. The drug will face its first patent expiration in 2027. Second, the company has several pipeline candidates that could help diversify its revenue stream. These include parsaclisib, which is currently being tested in phase 3 clinical trials as a potential treatment for mantle cell lymphoma, among other illnesses.

Naturally, Incyte also intends to grow its revenue from its other approved drugs. This list features cancer treatments Monjuvi and Pemazyre, both of which were first approved last year. Incyte may have lagged the market recently, but its shares have done much better over its entire history as a public company. And thanks to its strengthening lineup, this biopharmaceutical's shares are likely to rebound. Investors willing to be patient should consider adding this healthcare stock to their portfolios.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.