Cheap ThinkPad Recommendations

So, currently I need a new laptop as my current Dell Inspiron 3840 (Intel Core i5 8265U) is really not doing the job. Even when doing basic tasks (just with 1-2 chrome tabs doing nothing) it lags! I can't even get any of my work done. As of right now, I'm 15, and my parents promised that they'll buy me a new laptop if I get good grades by the end of the year. But currently, I really need a new laptop, so I thought to myself of buying a used ThinkPad as an investment laptop, any recommendations for around RM500 (100 USD)? Any help would be apprieciated.