Former VP of Innovation @ Gett - (Ride sharing, 4 to 1500 people in 4 countries) Also: Entrepreneur (3 startups), Mentor, Husband, Car racer (wannabe), recovering software developer (sometimes falling of the wagon)
I've watched different companies struggle with customer acquisition, and I myself struggled with it. I doesn't matter if its a physical product, a service or an app. Attention costs a lot of money, usually more than we can afford.
Paid acquisition should never be your main driver of new users, it will almost never pay for itself on its own. The only way to create a sustainable business is to have enough organic growth. I would suggest using your marketing budget not on generating direct sales but rather on cultivating channels that can grow organically.
There are many ways you can achieve this. Some tactics that are commonly used: Offer free products in exchange for "honest" reviews (https://www.amazon.com/gp/vine/help).
Find influencers (read people that are active on social media) that might have interest in your product, in your case - outdoor people - hikers, travelers, etc. Send them free samples, ask them to recommend it to their users if they like the product.
Another avenue I would suggest exploring is going to B2B or B2B2C. Camps & resorts for example would be places that probably have interest in product. Reach out to them, send them free samples. Offer them to purchase it, or to sell it in their gift stores.
I would be happy to discuss this further, answer questions and offer more advice.