Simple answer if you are worried about costs you will struggle. Ecommerce is a spend money to make money industry. Meaning the more you put in the more you will get out.

My strategy for any store launch is starting with one campaign, 7 adsets at $10 a day. Each adset with 4 creatives and one interest. This means you will spend $70 per day.

Then you need to let FB ads optimize which takes 3-4 days so you need to keep the ad running until it optimizes. Dont even expect sales until it is optimized. So this means you will be spending around $280 those 4 days. If you dont get any sales then you need to test more.

Bottom line the more you test in the beginning the more you will get out. If you can afford to do 2 campaigns at 7 adsets each and $10 a day each then do it. The more interests you target the faster you will get data and find your audience.