It’s ok to sell. If people subscribe to an e-commerce site, they expect you to sell. But don’t make them feel as a marketing target. Send an email that you would like to get yourself.
Use 70% - 30% rule for your email content.
70% of emails should give value, make them smile and surprise them. 30% of emails can sell. Sure, you can’t predict when someone needs your brand. Humans are complicated. Just make your audience curious to open your next email.