Samples are a powerful tool for attracting new customers.
I was considering buying a book this morning but I wasn't sure if it would be relevant. Luckily the publisher created a PDF sample I was able to read before I bought it.
Samples are pretty much required with digital items and items that can be digitized easily (e.g. books) these days. At the very least some sort of demo model is needed for wary customers to try out before they buy.
Many products beyond digital can benefit from samples. Anything usage-based (food, single-use packets, etc) should have some small sample that a customer can get. Even if they have to pay a token amount, that's a worthwhile product to develop.
Some things can't easily be sampled. A new printer or shoes wouldn't work. Unless you're going to send the left shoe for free and make them pay if they want the right shoe.
If you get creative, you might be able to create a partial sample. Sure whole shoes can't be sampled but could you send out a small piece of the material they are made out of? That would let the customer compare the color and texture. Or maybe some pages printed out from the printer to show its printing detail and color handling?
Take the time to brainstorm how to get samples of your best products into your customer's hands. Even if they aren't perfect examples of the product, it's a worthwhile step to counter some objections customers might have.
Once you have the sample developed, you can then use them to convert your existing buyers into repeat buyers. Toss a sample or two into each order for free with a note about which product they've from. Coax them to order that product in their next order.
One surprising benefit of the product analysis in Repeat Customer Insights is seeing how effective sample products are. Using the first orders, it can measure how sample products lead to repeat buyers and how much those customers are spending.