I agree with everyone that good SEO is the best thing you can do to get found, but I think search ads could help if you're in a saturated market and I think it can help with the really broad searches. I think my SEO is pretty good and I appear high up in most of the searches that I have tagged/titled for, but I'm not at the point where I will be found in some broad searches.
For example, pink bracelet, there are over 97,000 and I don't appear in the first 20 pages. So I think in searches like that where good SEO can only do so much that search ads could help. At least there is a chance of getting some views and increasing relevancy, even if a sale doesn't come out of it.
That being said I haven't used them a whole lot myself, but I tried them, got 3 sales and made more than I spent. So I do think it's worth a try especially if you set the budget at $5/week.