Plan a loyalty or referral reward

You're helping me plan a simple reward for returning customers or referrals. This is a plan for me to check.

What we offer and our prices: [WHAT YOU OFFER AND ROUGH PRICES]
Our customers: [E.G. LOCAL HOMEOWNERS]
How often customers usually come back: [E.G. ONCE A YEAR, OR "DON'T KNOW"]
What we can afford to give: [E.G. UP TO $30 PER NEW CUSTOMER]
How we'll keep track: [E.G. A SPREADSHEET OR OUR CRM]

Please:
1. Suggest two or three simple reward ideas that fit my business, and say which you'd pick and why.
2. For the one you'd pick, explain who qualifies, what they get, and when.
3. Write short wording to tell customers about it.
4. Suggest how to track it and how to tell if it's working.
5. List anything I should check, such as terms and conditions.

Rules:
- Stay within what I've said we can afford.
- Keep it simple enough to run without new software.
- Don't invent figures about how well rewards like this work.
- Anything sent to customers is a draft for me to check first.