I've had an online hobby business for the past 10 years selling antique and collectible items (all transportation related). My inventory is hundreds of one-off items, each of which appeal to a different type of collector/enthusiast.
I am currently selling primarily on eBay, but also use Etsy, Instagram, Kijiji / Craigslist, a couple enthusiast forums and my own website (very low traffic currently).
What are the best strategies to use to market a business of this type on a very limited budget?
I think you're on the right track with the likes of eBay, Instagram, and Etsy. Those sites have established communities interested in what you have to offer.
That said, each of those platforms have different optimization techniques to reach the right audience. For example, using proper hashtags on Instagram will likely result in increased traffic. Spending some money on Etsy's pay-per-click ads will result in fresh, targeted traffic.
I've helped brands around the world increase their reach through optimization with varying budgets. I don't believe in "one-size-fits-all" approaches, as each market has a unique audience, product, and seller (you) - those are important considerations before launching any type of sales campaign. I'd be happy to schedule a call with you to discuss more in detail.
These are all great channels to be visible on. In some cases, depending on the product, I would recommend Google PPC or shopping ads since you have your own website.
Otherwise I would say Facebook or develop/build an Email list to eventually integrate email marketing in to your strategy.
Why Facebook? Their resources and how you can fine tune audiences really allows you to spend your budget in a smart way.
Why Email? Email marketing is the best way to remind people that you're alive and say "Hey, I have something that you might like!" And if they don't buy anything, at least you have them pixeled on your site and you can re-target them.
I'd be happy to discuss more on call. I'm new on Clarity but have over 10 years experience selling and marketing online. I'm offering free calls to help boost my account. https://clarity.fm/morrisshipper/freebie
1. These days, I have seen lot of conversion happening from Facebook groups. Try targeting that. I am sure there would be few highly engaging groups which have your target audience.
It was also worked in for me which is B2B.
2. Though I understand that you are selling through online but I am sure, there must be few fairs happening in your area where you may find plenty of target audience. Explore that as well.
Another strategy is to connect with newsletters and blog sites that your best customers subscribe to and read frequently. If you are not sure, select a random few past customers and ask them directly. Then send an email query to the publisher or editor of these media and offer to serve as a go-to expert for future Q&A content about collectibles, etc. Perhaps the editor would accept a short guest post that you could submit along with a link back to your business website. In many cases, the only cost to you is your time. This is worth exploring. I would be happy to discuss other strategies with you if you will contact me.