just did a bit of research and found out that amerimutts have a law against email spam BUT with certain exceptions
>Unsolicited commercial emails are legal under the CAN-SPAM Act only if they follow strict rules. Senders must use accurate header information, provide a real physical postal address, and include a working way to opt out. Violating these rules carries fines up to $53,088 per email.https://www.ftc.gov/business-guidance/resources/can-spam-act-compliance-guide-businessso if you spam someone's email with a product with a way to opt out then it's legal
it doesn't mention any specific limits about how many messages you can send at a time though