Tier-Based Rewards Applet

I need an applet to calculate a tier-based reward system, triggered by purchases. The project is urgent and needs to be completed ASAP.

Key Requirements:
- Calculate rewards based on purchase data
- Support multiple tiers in the reward system
- User-friendly interface
- Integration with existing systems (if any)

Ideal Skills and Experience:
- Experience in developing reward calculation tools
- Strong programming skills
- Familiarity with tier-based reward systems
- Ability to deliver on tight deadlines