Spare cash can be invaluable when stocks are crashing. It gives you flexibility and the opportunity to buy stocks on the cheap without having to sell anything else in your portfolio.

Even if you have just $5,000 waiting to deploy, now could be a fantastic time to buy some stocks with the market crashing this year, especially growth stocks that are going through massive drawdowns. Two stocks that are prime candidates to turn your $5,000 into $50,000 are Spotify Technology (SPOT 2.86%) and Autodesk (ADSK 2.54%).

Here's why Spotify and Autodesk have explosive growth potential this decade.

1. Spotify: Cheap with optionality

Spotify is the leading music and audio streaming service worldwide, excluding China. Last quarter, it had 433 million monthly active users (MAUs), up 19% year over year. Spotify's biggest moneymaker right now is its premium tier, an ad-free music subscription that lets people download music for offline listening and offers popular algorithmically generated playlists. Premium subs hit 188 million globally in the second quarter, growing 14% year over year.

Premium revenue was around $2.4 billion last quarter, or $9.6 billion on an annual basis. This segment is barely profitable right now. However, with gross margins of 28% that have steadily grown over the years, Spotify is guiding the segment to hit 10% profit margins once it slows down its marketing spending to acquire new users. According to management, this improvement should take place in the medium term, which points to a timeline of roughly two to three years. With a 10% margin, that would give the premium subscription business $960 million in annual profits at its current revenue level.

With Spotify's current market cap of $15.8 billion, the stock would trade at a price-to-earnings ratio (P/E) of 16.5 using these assumptions, which is below the market's current average of 18. And this is in an industry (music streaming) set to grow at a double-digit annual rate this decade, so this subscription revenue should be significantly higher three to five years from now.

Of course, these aren't apples-to-apples comparisons because Spotify's premium business isn't profitable today. But I believe at current prices, investors are getting everything that isn't Spotify's subscription business as a nice little cherry on top. And that's a good thing because the company is investing in plenty of other audio opportunities. These include ad-supported music (which the company has offered for years), podcasts, audiobooks, and live talk shows (similar to the radio).

Most of these new initiatives will be ad-supported, which means investors should closely track Spotify's advertising revenue. Last quarter, ad revenue grew 31% year over year even amid a slowdown in the advertising market, which shows the progress the company is making with all these investments.

If Spotify can succeed with some or all of these new projects while continuing to chug along with the premium subscription business, I think the stock has a good chance to deliver 10x returns this decade.

2. Autodesk: Dominant in multiple software markets

Autodesk sells software products for the architecture, engineering, construction, manufacturing, and visual effects industries. With dozens of different products that it has bought or built over the years, the company has leading positions in many fast-growing software markets. 

For example, there's one of its most popular software products, Revit. It's the leading product for architects using building information modeling (BIM) standards, which are becoming the go-to standards for governments around the world when designing buildings. Analysts expect the market to almost double from 2021 to 2026 to $10.7 billion, which should be an easy tailwind that Revit -- and Autodesk -- can ride.

The company also provides construction management software with its suite of Autodesk Construction Cloud products. The construction industry is one of the least digital-savvy, with many worksites still using pen and paper to manage operations. The company is looking to change this with products like Autodesk Build, which grew MAUs by 45% quarter over quarter in the second quarter. It is only a small part of Autodesk's overall business right now but has the potential to be a big revenue driver in the second half of this decade.

Autodesk management is guiding for just over $2 billion in free cash flow this fiscal year, the best profitability metric for a subscription software business because of the way upfront payments are deferred on the income statement. With a market cap of $41 billion, the stock trades at a price-to-free cash flow (P/FCF) ratio of around 20 (market cap divided by free cash flow), which is just above the market's average P/E of 18.

With a strong track record of double-digit topline growth and multiple industry tailwinds, Autodesk looks like a great 10x candidate this decade, starting from its current valuation.