I’ve been spending $10/day for the past 8 days ($80 total) on a campaign and got 1 sale so far worth $25.
Would you kill this campaign even though it got a sale?
Obviously making $25 through $80 ad spend is not great.
You need to
-test different products
-test more angles
-test different creatives (different ads/different landers)
-fix your targeting
-or- you need to exclude placements, which i can't really say with confidence since you didn't say where you are running your ecom ads at
These are "goods" results man. Ofcourse the sale could be a lucky shot, but spend 10 bucks more and maybe 2 sales more appear which makes your case totally different. Try to see where you can win simple and fast;
- your ads fully optimized? compare CPC/CPM cost and see if you are at bottom price already. If not, make your ads better.
- lander/conversion rate - what are quick wins here? let experts check your sales pages and/or flow
And what Atilla is saying ofcourse.
You got a sale, which is great, because you most likely have a working product : unless it was a lucky shot as stickupkid mentioned already. I would definitely run it for some more to see if any more sales would happen.
And on top of that : did you collect some emails on the go for example? Are you using some retargeting pixels? Do you have any unfinished orders - maybe someone will return later on ...
With ecom, you need to look at the bigger picture too, direct sales is not everything ... think about returning customers and work on that.
I don't really do ecom that much, except for client work, but I would spend more before making any conclusions. I.e. test a lot more ads, ad varieties etc. Also dig into the data and see where the bottleneck is, whether it's too high CPC, poor converting lander or drop offs before checkout. Just go through the funnel.
So i'm still going and testing stuff.
For example, here's what some of my ad sets look like:

As you can see 1 and 3 are sorta my "winners" but the problem is that the majority of sales in row 1 came in the first two days and they just stopped the last few days.
What should i do in this case when sales are being made, I'm in a positive ROI but sales aren't consistent?
First of all your CPC it too high, CTR too low. Try better targeting or better images/videos. Lowering the CPC gives you much more space to test and gain more sales to find a consistent funnel.