Hey Donald, the best way I've been able to build my list without it wiping out the budget has been with contests and giveaways.
I always thrown paid budget behind it as, if done smartly, that's what allows you to get a large influx on new subscribers in a short period of time. The last list buildng campaign I ran we were getting subscribers for as low as 0.060c (thru trial and error) and built a list of over 781 new subscribers in just ten days.
I wrote a bit about the process within this Shopify case study here.
I also saw a really great post about a store in the same niche as you which I thought you might find interesting - may even be worth reaching out the store owner.
Good luck with the launch.