The second round of economic stimulus checks will soon be in the hands of many Americans. Direct deposits could hit bank accounts beginning this week, and paper checks and debit cards will be mailed shortly afterward. 

An extra $600 will help many individuals pay bills or add to their emergency funds. Those are absolutely the highest priorities for your stimulus money. Once you've addressed those crucial items, investing for the long term is a great way to use the added cash. If you're looking to invest your stimulus check, here are three of the best stocks to buy right now.

Economic stimulus check next to smartphone and $100 bills

Image source: Getty Images.

1. Etsy

Probably the most important thing to know about Etsy (ETSY 0.34%) is this: 88% of buyers say that the online e-commerce site has items they can't find anywhere else. Etsy's platform connects 69.6 million active buyers with 3.7 million active sellers in a marketplace for unique handcrafted goods. And those numbers are growing.

Etsy stock has soared close to 300% so far in 2020. This impressive performance was driven in part by the COVID-19 pandemic, with face mask sales boosting revenue significantly in the second and third quarters. During both quarters, the company also reported an influx of millions of new customers and returning customers who hadn't made purchases in over a year.

This momentum isn't likely to evaporate after the pandemic ends. Etsy found that buyers increased their spending by more than 50% year over year in the third quarter, excluding face mask purchases. Customers simply like the platform and are buying more products on it.

Etsy has only begun to scratch the surface of its full opportunity. The company estimates that it has a 5% market share in the $100 billion "special" products retail market. But the pandemic has caused management to realize that its actual addressable market is much larger. With its tremendous growth prospects and laser focus on serving buyers and sellers, I think that Etsy should generate huge long-term returns for investors.

2. Fiverr

Like Etsy, Fiverr (FVRR 3.74%) is an e-commerce company. But instead of connecting buyers and sellers of handcrafted goods, Fiverr connects freelancers and businesses for digital services.

Its stock was sizzling hot in 2020, skyrocketing more than 730%. CEO Micha Kaufman said that the company is benefiting from "sustainable trends in businesses upping their investments into digital transformation and their increased willingness to adopt a remote and flexible workforce."

The company estimates that its addressable market totals $115 billion. Fiverr expects to make close to $187 million in revenue in 2020, well below 1% of that addressable market. 

Capturing more of that market shouldn't be a problem. The workplace is changing into one where teams work digitally from anywhere. Fiverr is rapidly expanding into new markets, most recently launching its platform in Brazil and Mexico. My view is that this stock is likely to be a big winner for a long time to come. 

3. Innovative Industrial Properties

A real estate investment trust (REIT) might seem boring compared to the excitement generated by Etsy and Fiverr. But Innovative Industrial Properties (IIPR -0.17%) isn't an ordinary REIT.

IIP focuses on the U.S. medical cannabis industry. It provides a valuable service to medical cannabis growers that face challenges obtaining capital due to restrictive federal laws. IIP buys these companies' properties then leases the properties back to them. These sale-leaseback transactions give the medical cannabis operators much-needed cash and give IIP a nice long-term revenue stream.

The U.S. medical cannabis market is growing like a weed (pardon the pun). Two states voted in November to legalize medical marijuana, bringing the total number of states where medical cannabis is legal to 35. IIP currently owns 66 properties in 17 states. Many of these markets are still only in their early stages and continue to see robust growth.

IIP stock jumped more than 130% in 2020. I think that it could double -- or more -- in the new year as the company adds more medical cannabis properties.