I'm starting a business similar to Zazzle, but geared more towards B2B products. The sales process is unfamiliar territory for me.
What should I do if companies ask for samples? Should I charge for them or provide them for free?
Since the products have to be customized for each company, there is a slight overhead in creating a small batch of samples.
Depends on how much overhead it costs you to create the samples. If it's negligible, try sending them for free for some time and see if it leads to more paid customers. You will have to track the numbers to get a clear view.
You never know if you are missing out on more customers (and higher overall revenues) by not sending the samples for free.
Conversely, you might find out it doesn't lead to a significant amount of more clients to justify the cost of the samples.
TL;DR Try out both to test which works best for your bottom line.