How small is "small?"

To begin with, interact with them and offer to answer questions or recommend resources (for free, no affiliate commissions)

See what appeals to them.

When it comes to making money from it - it also depends where your list comes FROM. For example, if they're a list of buyers of a high-priced product then they're going to be a lot more responsive to higher-priced offers. If they opted in for a free ebook, you should start with much lower-priced offers.