Here is a ready-to-use English letter with answers to your questions. You can replace the placeholders with your own name and details.
Dear [Friend’s Name],
Here are my answers to the questions you asked for the English assignment.
What is your best purchase? My best purchase is my bicycle. I bought it two years ago for about $150. It has saved me money on transport, keeps me healthy, and is very reliable for daily commutes to university and running errands.
What is your most expensive purchase? My most expensive purchase is my laptop. It cost around $1,200. It’s essential for studying: I use it to write essays, do research, attend online classes, and run software for my courses. It has been worth the investment.
Which purchase do you regret? I regret buying a fancy kitchen blender that I rarely use. It was expensive and bulky, and I found I could do most things with the tools I already had. In the future I’ll think more carefully before buying big gadgets.
Well, that’s my answer. If you’d like me to adjust the tone or details, tell me.
Best regards, [Your Name]
If you want, I can tailor this for a formal letter (to a teacher) or make it more concise. Just tell me the required format and your own experiences.