Kia ora Good Sport,
Marketing on a budget can certainly be a challenge! Here are my thoughts for your situation.
Maree made a great point about targeting influencers. Particularly on Instagram and YouTube.
Influencers often are incentivised by payouts to promote your product, but small-time influencers don’t cost much (from $50-200 per shoutout) and some of them will promote a product for free samples alone.
If you don’t like the idea of researching and finding influencers yourself, you can use a tool like https://izea.com/.
**Content & Social**
I can see that you have a fair amount of blog content on your website (I’m assuming http://www.wearegoodsport.com/ is your website) and post a lot on Facebook. Facebook can be very profitable for products like yours but to accelerate progress on FB you really need a budget for a FB ad campaign. So your efforts could be spent elsewhere until you can put together a budget for a Facebook ad campaign.
Since you seem to put a lot of effort into content, search engine optimising your product pages and blogs could be beneficial but would be a slow-burn before you see results. The key thing to focus on is trying to find out what all the keywords and questions the public are asking Google and incorporating those into your content. If you can answer those where others don’t then you can get a lot more search traffic. A great resource for finding those questions out is https://answerthepublic.com/
One important thing is that if you’re planning to have your website as the main source of revenue; it could do with some improvement. It appears to be a WooCommerce website utilising a very basic template. I understand that you may not be able to afford to pay for professional help at the moment, but it would be worthwhile investing a small amount in a better premium WooCommerce template. You can turn your website into something a lot more professional with a theme for under $80 and a bit of elbow grease (there’s a huge range at https://themeforest.net/category/wordpress/ecommerce/woocommerce).
Otherwise, you’ll be spending a lot of time, effort and/or money on driving people to a website that doesn’t convert.
I hope that helps!