Write a Referral Program Email

Write an email launching a referral program for existing customers of [PRODUCT / SERVICE]. The referral offer is: [DESCRIBE THE OFFER, e.g. give $20, get $20 / 1 month free for both]. The email should: open with genuine appreciation, explain the referral offer clearly in one sentence, spell out exactly how it works in 3 simple steps, address the "what is in it for my friend" angle, include a clear CTA with the referral link, and add a PS that creates mild urgency. Subject line: 3 options. Length: under 250 words.

Tone: warm and rewarding.