You've heard it before: It takes money to make money. However, that doesn't mean that you must have a lot of money to invest upfront to generate sizzling returns.

There are stocks you can buy with relatively modest initial investments that can pay off big-time over the long run -- and sometimes, even in the short run. If you've got $2,000 to invest now, here are three unstoppable stocks that have the potential to more than double your money pretty quickly.

Marijuana stocks are hot right now -- especially those of U.S.-based companies. Multistate cannabis operator Ayr Wellness(OTC:AYRW.F) is a great example. Its shares skyrocketed more than 150% last year and are up by close to 35% so far in 2021.

There's a good reason for that impressive performance. Ayr's revenue and adjusted earnings before interest, taxes, depreciation, and amortization (EBITDA) continue to grow robustly. This growth has come from the company's operations in Nevada and Massachusetts. But Ayr is already expanding beyond these markets.